Hibiki Kuze, is waiting for his friend, Daichi Shijima, after finishing their practice exams. While discussing their future, Daichi introduces and registers them onto a recently popular website called "Nicaea", a video delivery site that allows people to see videos of their friend's death. Later, at the train station, they receive videos from Nicaea that show both of their deaths by an oncoming train at that exact station. Shortly after, before the train arrives, an earthquake occurs, causing the incoming train to derail and cause the same devastation they saw in the videos. On the verge of death, Nicaea offers Hibiki a second chance to live and a Demon Summoning App is forcefully downloaded into his phone. He and Daichi awake to find the station in ruins with most of the people dead. They then witness vile wolf-like creatures eating the corpses of the recently deceased. As the creatures turn their sights on them, rescued fellow classmate Io Nitta and Daichi inadvertently manifest demons from their cell phones which repeal the attacking creatures and allow them to escape. Making it back to the surface, they find that all of Japan has met with the same type of calamity before a strange organization takes over rescue operations, with the officer in charge pondering that humankind must survive "Judgement Day" even if it means using demons. With nowhere to go, the three decide to stick together and while waiting in Roppongi, the crowd is attacked by a demon called Dubhe. At the same time Hibiki receives another video showing Daichi's death, before Daichi bursts out of a corner with a delivery truck, intending to ram the demon. As the truck explodes, Hikibi, overcome with emotion, manifests his Avatar: Byakko, a tiger like demon which he manipulates and successfully destroys the Dubhe. In the aftermath, Daichi had been saved by another one of Io's demons, a pixie-like creature before the group is approached by the Japan Meteorological Agency: JP's. Elsewhere, a mysteriou

Hibiki, Daichi and Io are arrested by the JPs and brought to a secret underground base located at the National Diet Building. Here, Commander Makoto Sako, explains to Hibiki that the JPs protects Japan from "paranormal anomalies" before she introduces the JP's Chief, Yamato Hotsuin who says that Hibiki's demon Avatar: Byakko is unique, being one of the four symbols of the Chinese constellations. Furthermore, he explains that the Dubhe was only one of 7 creatures called the Septentriones, each of which will appear in the next six days and should the JPs fail to defeat them then the world will disappear. As the JP's scientists begin to analyze the demon summoning app, Hibiki ponders on Yamato's words. The following day, Makoto releases them by taking them to an emergency shelter in Chūō. Here, it is discovered that a rumor of demons running amok is spreading. As Hikibi looks around at all of the refugees in a church, a winged-demon attacks and Hibiki summons Byakko to protect them. As Hibiki fights an endless swarm of the demons, Makoto shows up with her demon, Power and helps Hibiki defeat the winged-demons by destroying the rogue cellphone which had been summoning them. In the aftermath Hibiki walks away when he realizes the refugees are afraid of him, but gains resolve, along with Daichi and Io to help the JP's after a child thanks him for protecting them. Back at the Diet Building, Yamato outlines Hibiki, Daichi and Io's first mission: to locate and rescue missing JP's scientist Dr. Fumi Kanno. In the epilogue, Yamato has a short dialogue with the mysterious man about Hibiki, while elsewhere, somewhere in Nagoya a man remarks that their "plan" shall be set in motion.

Under Yamato's order, Hibiki, Daichi and Io rides on the secret train of JP's to Osaka to help find their chief scientist, Fumi Kanno, who has lost contact recently. They are greeted by another summoner of JP's, Hinako Kujou, at their arrival, but the other summoner Keita Wakui is less welcoming of the three fellow summoners and is returning to his mission of hunting down malignant demons. At the Osaka headquarter, its computer system is under attack from the whole Japan's network. At the same time, Hinako receives Keita's death clip, Hibiki instantly concludes that the scene of Keita's death is related to the hacker attack. Although Hibiki asks an operator to inform Keita not to head to the location of his death scene, Keita cannot receive the call due to being ambushed by Gozuki and Mezuki. All four summoners head to the abandoned theme park where the hacker attack originates from. Hinako commands Lilim to rescue Keita from falling off the stairway, supposedly averting Keita's death fate. When planning for reaching the very location of the hacker, they discover it is Fumi brainwashed by Botis, the demon behind the hacker attack. After defeating Botis and destroying Fumi's computer equipments, Botis reappears, blasting the whole area with lightning. Daichi manages to save Fumi, but Keita who reflexively pushes Hibiki away from the range of the lightning is hit then sent falling down the stairs to his death, just as the Nicaea death clip had predicted. Meanwhile, JP's detects the arrival of a new Septentrione in Osaka due to the lost of barrier from the hacker attack.

Following Keita's sudden death, Hibiki remains visibly shaken due to the fact that they couldn't prevent it. As Merak arrives in the city, Yamato has JP's members move Hibiki into position to intercept it. At the Osaka Juso Ohashi Bridge, the Japanese military tries and fails in their attack against Merak while Botis and "The Anguished One" discuss the state of affairs. With of the loss of most Osaka's spiritual barriers, Merak fully manifests itself and makes its way to the final barrier - "Tsutenkaku". Meanwhile, as Hibiki is deployed into the field, Hinako and Io discuss his mental state due to Keita's death. Meanwhile at the Umeda Sky Building, JP's summoners try to stop Merak with a swarm of Itsumade but it kills them all in an instant. As Io heads to Hibiki's location, Merak then launches a devastating ice attack, at the "Tsutenkaku" barrier, which survives, but the attack leaves a path of destruction and kills many more people, upsetting Hibiki. Not wanting any more people to die, Hibiki abandons his post and proceeds further up the battleground to confront Merak. Io arrives just as Hibiki departs and Yamato sends a "replacement" for Hibiki. Hibiki arrives at the current battleground at Kawaramachi in the Osaka Chūō-ku Ward and intervenes in Hinako and a platoon of JP's summoners fight against Merak. Hibiki has Byakko unleash a strong lightning attack at Merak, which doesn't have any effect. Merak counterattacks and Hinako protects Hibiki but gets severely injured which then shatters his fighting resolve. In the wake of the attack, the "Anguished One" approaches Hibiki and introduces himself as Alcor. He informs Hibiki, that because of his "choice" to fight, Io has taken his place at the final defensive line, causing Hibiki to head over there. Io's feelings allow her to summon Kikuri-Hime and proceeds to attack Merak with support from the JP's summoners. Although Kikuri-Hime manages to severely damage Merak, it sheds its outer layer and begins charging up i

Makato briefs an infiltration team of JP's agents on their way via train to retake the JP's Nagoya Branch from Ronaldo's control. At the same time, Daichi and Io stow away on the train and ponder why Hibiki left them behind. Just then, they are shocked to receive Hibiki's death clip and resolve to save him themselves since the only people able to receive death clips are friends. In the meantime, the JP's tries to reassess the situation after loosing contact with Hibiki and now their infiltration team as Dr. Kanno repairs the damage to the JP's Osaka servers. Meanwhile in Nagoya, Jungo Torii and Airi Ban plan to infiltrate the JP's Nagoya Branch and retake it from the insurgents, although Airi also speculates that the JP's and the Resistance (Insurgents) had prior knowledge of the calamity. Elsewhere, Daichi and Io arrive in Nagoya to discover a Resistance camp handing out rations to civilians. Just then the camp is attacked by a swarm of rogue Legion demons. Daichi and Io summon their demons to intercept, however the swarm proves to be too large. Hibiki then appears in the background with the demon Suzaku and incinerates the swarm. As Hibiki leaves, Daichi demands from a nearby insurgent about his whereabouts to meet the insurgent leader, Ronaldo. Later at the Nagoya Branch, while an insurgent member and JP's medic, Otome Yanagiya argue over the state of affairs, Ronaldo appears with Hibiki and tells them that once all the Septentrione have been defeated, Yamato intends to create and become the leader of a new Meritocratic governing power in the aftermath. He further states that Yamato manipulated both the JP's and the Japanese Government for that ambition and when he, a former detective and JP's agent found out i.e. the "Hotsuin Family Secret": Yamato's plans and their predictions of the Septentriones, an attempt was made on his life. Still in a doubt, Ronaldo reminds Hibiki of how many lives were lost at Yamato's order during Merak's assault and that a world in Ya

Airi and Jungo sneak into the JP's Nagoya Branch through the air ducts, while elsewhere, Daichi and Io rush to Hibiki's location in order to prevent his death. As Ronado, Hibiki, Joe and Otome scout the Nagoya TV Tower in anticipation of the third Septentrione, Otome is hesitant to fight, especially when the JP's members such as herself have been told little to nothing about the Septentriones, although Ronaldo states that they should have no problem since their demons are much stronger than those used by JP's summoners. At the same time, as Hibiki ponders on Nicaea's origin and his power. Later, back at the Nagoya Branch, Otome and Hibiki have a brief discussion comparing Yamato's methods versus Ronaldo's methods. At this time, Daichi and Io arrive and tell Hibiki about his death clip while Makoto covers for them at the JP's Headquarters. Daichi and Io try to get Hibiki to return with them but he states that he can't because of the imminent Septentrione attack. Eventually both group's shared feelings of wanting to protect each other, cause Daichi and Io to remain in Nagoya with Hibiki. Meanwhile, as Resistance members begin clearing out the base's Command Center, Airi and Jungo inadvertently fall through the air ducts and ensue in a battle with the Resistance members. Ronaldo enters the fray and tries to reason with them, although Airi becomes far too entertained by the heat of battle that she ignores and attacks Ronaldo, even after Hibiki pleads for them to stop. At this time the manifestation readings suddenly increase and the Septentrione: Phecda manifests itself directly in the Command Center to everyone's shock. Ronaldo immediately issues emergency orders and has Airi and Jungo help attack Phecda along with Joe. As the group launches an assault, their demon attacks are not strong enough to damage Phecda, who counterattacks with an electrical attack, wiping out their demons along with the Branch's main power. Just then Hibiki, Daichi, Io and Otome arrive and att

As the exchange between Hibiki, Yamato and Alcor continues, Yamato rejects the notion of a person's fate being predetermined by the death-clips. As Hibiki is forced to make a choice of staying with the Resistance or returning to the JP's with Yamato, Ronaldo tries to sway his decision but is stopped by the demon Bifrons. As everyone realizes that Alcor isn't using a cell-phone to control the demon, his origins are questioned by Hibiki to which he responds that he genuinely doesn't know, only that he isn't their enemy. Ronaldo has the Resistance summoners surround him with demons, but Bifrons easily incinerates them. Alcor goes on to calmly reveal that he is the creator of Nicaea and the Demon Summoning App, which he gave to humans as a means to fight the Septentriones, finally remarking that it allowed him to find a new "Shining One" in Hibiki. Ignoring the exchange, Yamato outlines that the next Septentrione will appear simultaneously at the spiritual barriers in Tokyo, Nagoya and Osaka with Fumi adding that only high level demons would be strong enough to face them from now on. As he leaves, Yamato entrusts Osaka to Hibiki and leaves the Resistance in charge of the Septentrione in Nagoya although both Hibiki and Ronaldo state that they will not be Yamato's pawns. Hibiki concludes that at the end of the week long Septentrione battle, he will stop Yamato's plans. Afterwards, Alcor has an exchange with Bifrons and Botis on his actions which hint at stopping the "Purge of Polaris", while simultaneously as Yamato looks at having overused his power to control Ceberus, he recalls having rejected being the "Shining One" in favor of his ideals of stopping the "Purge" to Alcor in the past. The next day, as Fumi finishes work on a teleportation device, all the JP's and Resistance members submit for routine health checkups. Hibiki thanks Daichi for coming to his aid, while Io and Otome talk about the bonds they share with the people close to them, while Otome simultaneously t

Hibiki and the rest of the summoners fights against Megrez that have appeared simultaneously in Tokyo, Osaka, and Nagoya. However, Megrez will continuously revived unless the three main bodies are defeated at the same time. As the battle starts, Hibiki and Io summons their demons, along with Hinako who uses Berserker to avenge Keita's death, while Yamato uses his power that increased by the Ryumyaku tower and his demon Baal to stop Megrez' movement until the right moment. During the battle, Hibiki and Io received Ronaldo, Joe, and Otome's death clip that shows them died by Megrez' attack. Hibiki immediately tells Ronaldo to escape, but Ronaldo, Joe, and Otome decides to keep fighting since there are no summoners other than them that can defeat Megrez and resolves to avoid their fate like Hibiki does yesterday. As Megrez comes closer to the tower, Airi, who is enraged that the town where she shares her memories with her family and friends destroyed, summoned new demon, Lorelei, and stops Megrez' movements. After much effort, Hibiki, Yamato, and Ronaldo are able to land an ending blow to the three cores of Megrez at the same time, defeating it. But just before the Septentrion in Nagoya disappears, it uses the last of its strength to launch a final attack on the summoners. Airi and Jungo manage to survive the attack, however, Ronaldo, Otome, and Joe are killed in the blast, leaving everyone, especially Airi, Hibiki, and Io, devastated. As they tries to cope with the devastating loss, Hibiki is approached by Alcor who reveals that he is a Septentrion who works for a being known as Polaris, the cause of the world's destruction. Alcor proceeds to explain that he created the demon summoning app in order to give humans a chance of survival against Polaris's plan to strike judgement on humans by ending their existence. But hope seems lost as the world is slowly disintegrating into the Void.

Hibiki awakens on Thursday and to his surprise, finds Alcor waiting in his quarters. Over coffee they casually discuss the state of affairs. Hibiki, now believing that Alcor isn't a threat, gives him sanctuary in his JP's quarters, with a promise that he not reveal himself and what he actually is to anyone, for fear of creating a panic within JP's. Just then, Daichi and Io enter Hibiki's quarters and find Alcor, much to their shock. Although, Hibiki is forced to confide in them about Alcor's nature. Later that day, Airi and Hinako are selected by Makoto and Fumi to challenge the next Septentrione. Much to Hibiki's reluctance to let them fight, Makoto explains that the Septentrione: Alioth is scheduled to manifest in the Earth's Ionosphere, and hence, specialized long ranged demons that only Hinako and Airi can summon, stand any chance of attacking it. As Alioth manifests in the ionosphere above the Sapporo region, Hinako summons the demon Shiva at the Sapporo TV Tower while Airi summons the demon Kama over at the Kaitaku Memorial Park. Utilizing an ancient myth, the JP's has some Legion demons, bind Kama in chains and take it into position in the air. Kama's appearance angers Shiva and he attacks it with the Pasupata ability. The ability intersects with Alioth's core in the ionosphere and successfully destroys it. Afterwards, while everyone breathes a sigh of relief, Alioth's 50km outer shell plummets from the sky and falls over the Sapparo region, destroying the city and killing all the inhabitants, much to everyone's shock. Later, while going through Ronaldo's data, Hibiki struggles to come to terms with all who have died for Yamato's ideals. That evening, Yamato prepares a feast during which he tells Hibiki and co. of the coming of Polaris in two days and if they don't follow his orders they may die. Hibiki reveals to everyone that the JP's intends to use their encounter with Polaris to recreate the world the way they see fit, although, Yamato rejects this, stati

The following morning Alcor surprises Hibiki, Daichi and Io by making breakfast for them, while Io withholds her fate from Hibiki and Daichi. Later, Alcor visits Yamato and expresses his concern over what consequences Io's death would have on Hibiki, although Yamato shows no sympathy for Alcor's anguish. Finally, Io is summoned by the JP's while Hibiki and co. are briefed on the Septentrione: Mizar's abilities of self-replication. As the group expresses concern on a battle plan, Yamato and Makoto reveal to their horror, Io inside a machine connected to the "Brionac" and their plan involving Io's sacrifice for Lugh. Furious, Hibiki demands another plan, although Yamato's logic trumps him. Finally Mizar manifests in Tokyo prompting Yamato to begin the summoning for Lugh. Simultaneously, Hibiki, Daichi and Hinako receive Io's death clip, causing Hibiki to storm out of the JP's headquarters. As Lugh manifests, Yamato assumes control of it and releases the Ryumyaku Seal at the Tokyo Metropolitan Government Building to envoke the Dragon Stream - Shakko, while at the same time Io's mind begins to erode due to the strain of maintaining Lugh. Makoto explains that Shakko connects to a parallel universe and hence, is the only thing capable of banishing Mizar before it replicates infinitely and consumes their own universe, which Yamato manipulates through Lugh and thus defeats Mizar, just as Io's mind collapses. As Hibiki arrives at the Shinjuku National Stadium, Yamato orders him to destroy Lugh (Io) who has now gained control of Io's body. Enraged at being imprisoned by the Hotsuins, Lugh makes its way to the JP's Tokyo headquarters at the National Diet Building to take Yamato's life. Lugh appears and pummels the JP's defences with little effort, but remarks on Hibiki being a worthy opponent because of his summons. Hibiki tries to communicate with Io but Lugh insults Io's will before attacking him, knocking him off the side of the building, although he is saved by Yamato. Yam

Hibiki is put into intensive care at the JP's' Tokyo Branch. As the demon summoners look on, Io can't help but feel responsible for his current condition, although she is comforted by Jungo and Airi. Meanwhile, Alcor is visited by Botis and Bilfrons, the former of whom tries to attack him because of his supportive stance on the humans. Fumi updates the JP's phones with software capable of summoning stronger demons. The next day, Io, Daichi, Airi, Jungo and Hinako have breakfast together in a single moment of peace and officially introduce themselves to each other. As they go to exchange emails, they all simultaneously receive each other's death clips. Suddenly the last Septentrione: Benetnasch appears and destroys the Sapporo barrier with a single attack allowing the Void to consume the region. As Fumi outlines that it possesses the abilities of its predecessors, the Osaka and Nagoya regions are wiped out each with a single blast. Yamato then orders everyone to begin the operation. A flashback into Hibiki's past shows him growing up with strict parents. At a playground Daichi defends Hibiki from some bullies and the two quickly become best friends. After being able to enter high school, Hibiki's father warns him of choosing his friends carefully, but he chooses to reject this ideal and remain friends with the carefree Daichi. Simultaneously, Hibiki regains consciousness and tears at his sudden reminiscence. Meanwhile, Benetnasch eradicates the Diet Building in a blast equivalent to a nuclear explosion, rocking the city and exposing the Ryumyaku seal beneath its foundations. Here, Yamato has the JP's channel all of the Ryumyaku's power through him while creating a shield to defend from Benetnasch's attack. At the same time, Makoto and co. summon their demons and launch a barrage of attacks at Benetnasch which seem to overwhelm it. However, it suddenly splits part of itself off and emits a particular frequency that forcefully cancels their demon summons. Having antici

With the Trials of Polaris behind them, Alcor appears before Hibiki and co. and states that he intends on killing Yamato of his own free will and in doing so, entrusting the fate of the world to Hibiki, a battle which Yamato accepts. As their battle begins, Hibiki explains to Daichi and Io what would happen to the world if Yamato has his way after meeting with Polaris. While attacking Yamato with tentacles, Alcor realizes that Yamato had been steadily drawing him closer to the Tokyo Tower to enhance his use of the Ryumyaku. Afterwards, they take a short pause and exchange threats. Alcor expresses his support of Hibiki's future since he was treated as an actual person when with him, although Yamato retorts that Alcor should revert to being a mindless tool, and if so, he would be allowed to see his vision of the future. Just then, they both receive each other's death clips. Hibiki also receives their death clips and decides to keep his promise to Yamato by stopping him. Makato then makes her intentions of aiding Yamato until the end known, while lamenting on the pain she had brought to Hibiki and his friends under his orders. Makoto explains that before Yamato took her in, she had lost hope for the future, but he gave her a sense of purpose and brought a semblance of meaning into her life, and hence, is willing to aid him. As Hibiki tries to talk her out of it, along with Daichi and Io, receive her death clip, before she finally requests that they take care of Yamato before flying towards the battlefield on Power. As their battle continues, Alcor overwhelms Yamato, even easily destroying Cerberus. Although, since the Nicaea app is able to summon stronger demons based on a user's growth, Yamato tries to download stronger demons but not fast enough as it happens and is impaled in the leg by Alcor's tentacle attack. However, before Alcor can follow through and finish Yamato, he is distracted by Power before Makoto jumps in front of Yamato, acting as a human shield and is

Not having anymore hesitation to fight, Hibiki reminds Yamato of their promise of defeating him and having an audience with Polaris. As their battle begins, Yamato notes that Hibiki is driven by his anger towards him and his warped reasoning behind sacrificing the lives of everyone. Although, Hibiki defends by stating that as a human, he cannot allow such injustice to prevail, causing Yamato to question his own humanity. As Hibiki defends an attack using Shakko's power, Yamato acknowledges him as an equal and reveals that their current situation had all been part of a grand scheme put into motion by Polaris since the moment of their births. However since Polaris itself is flawed by its own nature, it had left it up to humanity to decide amongst themselves who should survive until the end, whilst citing the anomaly of Alcor's nature as proof of this. This truth shocks Hibiki, but Yamato simply brushes it off as semantics in his goal to reshape the world into a meritocracy. As their debate continues, Hibiki desperately tries to defend the previous world that he and his friends fought so hard to protect, although Yamato remains adamant in his reasoning that those with power have a responsibility to erase the cancerous nature of humanity's current train of thought which had lead to world built on corrupt foundations while simultaneously exposing Hibiki's naivety. As Hibiki tries to explain how people can work together, he tries to get Yamato to realize that they had been friends all along because of their actions, but Yamato rejects the very notion of friendship, claiming that it is weak. As Yamato starts to show injuries from his previous battle with Alcor, Cerberus weakens a bit and Byakko utilizes the opportunity to eradicate them both with a lightning attack. Hibiki once again tries to assert his friendship with Yamato, claiming that they don't have a reason to fight although Yamato chooses not to accept this, since disregarding his goals after coming this far would