The twin boys Migi and Dali live in an orphanage until one day they are adopted by a wealthy and gentle elderly couple, the Sonoyamas. However, they are not taken in as the two boys 'Migi' and 'Dali,' but rather as a single boy named 'Hitori Sonoyama.' While hiding their true identities and pretending to be Hitori Sonoyama, they hatch a plan to win over the Sonoyamas. Their scheme is highly successful; within just a day, they won the favor of the elderly couple. Inside the tent in their room, the two share a sly smile.

Migi and Dali have been fully accepted as members of the Sonoyama family. They behave just like real parent and child, but the twins notice that Mom and Dad are acting somewhat distant. Suspecting that the Sonoyama couple might be hiding something, the two discreetly begin to search the house and stumble upon an unexpected secret of the couple. Migi and Dali are shocked, wondering if they have been deceived. However, determined not to let things end this way, they execute a plan to retaliate against the Sonoyamas.