Spring has come to Moominvalley, and Moomin and his family come out of their winter hibernation. Up in Lonely Mountains Moomin, Snufkin, Sniff and Little My find a large top Hat, which they bring home. Too big to be worn they use it as a waste paper basket, but it is a Hat of magical qualities, and anything thrown into it changes into something completely different...

The magical Hat, which the Moomins tried to get rid of in the first episode, reappears, it got stuck on a sand bank in the river, which has turned to raspberry juice. Moomin recovers the Hat and hides it in the cellar, wanting to have a constant supply of juice. Little My drops a piece of string into the hat, hoping it will turn into spaghetti. However, the string turns into something quite different.

Moomin and his friends go mountain climbing, encounter a very depressed Hemulen, sunk in gloom because his stamp collection is finally complete and he has nothing more to collect They learn from him about a sailboat wrecked on the beach. They start repairing the boat, hoping to sail the seven seas. Deciding to start collecting plants instead, Hemulen gets over his depression, and they all go for a trial sail.

Moominfamily and their friends set out for adventure in their new sailboat, and finally arrive at a seemingly uninhabited island. It is, however, populated by some very strange creatures with whom Hemulen has an unpleasant encounter. A terrible storm hits the island and they decide to stay over night, pulling up the boat as far as she will go and taking taking refuge in their tent.

Our friends have forgotten to tie their boat up in the storm and are attacked by hordes of electrified Hattifatteners, who want their sacred barometer back. Swimming about after the storm Moomin and Snorkmaiden find the most exciting things brought by the storm, but the most exciting find is undoubtedly made by Snufkin.

One day two very small guests arrive at Moominhouse. They bring a suitcase, so Moominpappa knows they have come to stay and builds a small bed. Everybody is dying to know what`s inside the suitcase, which Thingumy and Bob guard day and night. The terrible Groke knows, however, and she is coming to get it.

After the visit of the Groke, Snorkmaiden finally finds out to whom the contents of the suitcase belong, but this only makes the problem worse, and it is with great misgivings they await the return of the Groke. Only Moominmamma has a plan, but will it work?

The Groke has gone, having been given a very special sea-shell which was a gift from Snorkmaiden to Moomin, who is now in trouble. Moominmamma's handbag disappears, and she promises the finder a huge party. It seems the Groke was not the only one interested in the contents of the suitcase, however...

Too-Ticky brings Ninny to Moominhouse view. Ninny has been frightened so often by her aunt that she has become invisible. Moominmamma concocts an infallible remedy, but will that and kindness be enough? Stinky does his best to see to it that it doesn't.

Very slowly Ninny comes back into view, but her face is still missing. Stinky does his best to stop her from becoming visible, resorting to very nasty tricks when the children play hide and seek. It appears that anger and shouting loud is even better than medicine and kindness for getting your shape back.

Snorkmaiden's brother has finished planning his flying ship, and has constructed a pair of wings so he himself can try out his theories, jumping of from the highest cliff in Moominvalley. But he is not the only one to think that flying is great - Stinky would like the wings for very Stinky-like purposes...

Moominvalley is hit by a terrible storm, and an old sailing ship is wrecked offshore, finally sinking. But, it is no usual ship - she is seen flying a black flag with a skull and crossbones. The pirates have made it to the shore unhurt and trouble starts when the captain, a terrible villain, grabs Snorkmaiden and holds her hostage, demanding a new getaway ship from the people in Moominvalley. The Inspector is frantic and helpless and it is left to Moomin to bring about her rescue.

After a tremendous downpour Moomin finds a very small dragon in a puddle. Smothering this most exotic of pets with love he expects great devotion in return, but finds that love is a fickle thing indeed, and particularly difficult to contain in a glass jar.

One day, Fillyjonk moves into the Moomin Valley with her three children. Although the Moomins hold a welcome party with a lot of unique idea's meant to please them, Fillyjonk just dismisses them as harmful to the upbringing of her children, strictly prohibiting them from playing with Moomintroll and his company. Her children try to follow their mother's BEHAVE-YOURSELVES type of orders at first, but their natural instinct as children gradually draws them into Moomintroll's circle of playmates.

During a spell of rainy weather Snorkmainden has crammed herself with stories about princesses and chivalrous knights. On the first sunny day she and Moomin climb a mountain, where Snorkmaiden sees what she believes is, an Edelweiss. Needless to say it isn't (no such things in Moominvalley), but they have to climb down to get it. Snorkmaiden slips, rolls down the mountainside and winds up in a faint. When she comes to she has forgotten all, and thinks she is of royal blood...

One day a flying saucer lands in Moominmamma's vegetable garden. It is apparently unmanned and she and Moomin salvage a strange box-like apparatus which looks rather home-made, but which has many remarkable properties. The Inspector is on the war-path trying to nab extra-terrestrials and when the Moomins find one, a runaway child, they have to hide him, quickly deciding that he has probably not come to invade Moominvalley. Their task isn't made any easier by the fact that the box-like apparatus has now made the Inspector iridescent, this fascinating the child so that he follows the Inspector everywhere.

Bored stiff with calm, sunny weather and stuck in his memoirs, Moominpappa craves adventure. Stinky decides to comply and provides a set of gigantic footsteps, leading up from the sea to Moominhouse. This creates a diversion, but is not enough and Moominpappa decides he and Moominmamma should elope (they never did it before because they had no one to elope from). Stealing off in the middle of the night they leave Moomin to fend for himself, something he doesn't manage all that well. Sniff and Little My help him cook and it is probably a very good thing that his parents haven`t managed to get very far...

It is hotter than ever before in Moominvalley. The river has run dry and everything is wilting. Going down to swim one day with the other children Little My finds a large wooden crate floating in the water and when they open it they find it full of strange-looking, tropical seeds. They plant them as they have nothing better to do and next night the rains finally comes, a veritable deluge. The seeds sprout and next day the house is surrounded by a jungle. Bamboo, orchids, fruit-trees, but also some much more dangerous plants...

Moominfamily and their friends have a great time in the jungle. The Hemulen is botanizing as fast as he can, everyone is eating tropical fruit and Moomin and Snorkmaiden play Tarzan and Jane, building a leaf hut. Suspiciously helpful, Stinky offers to get them some animals, too, so it will be more like a real jungle. He is as good as his word, but the animals that he provides are not exactly of the kind they had in mind.

Moominfamily have befriended all the wild animals that Stinky let out of the zoo (except the crocodiles and who wants to be friends with a crocodile, anyway?) and when the zoo-keepers come to take the animals back, the Moomins, aided by the Inspector, fend them off. But, also, the hot spell doesn't last. Autumn comes, the jungle withers in the cold and the animals huddles, shivering, in front of open fires, wondering if chilly freedom is really better than a warm zoo.

Again winter is at the door and Moominpappa and Moomin are collecting wood to keep the house warm during their long hibernation. Moomin is feeling very sad because it is time for Snufkin to go away on his long annual trip. Moomin talks his parents into letting him go along, but Snufkin says no - he needs some time to himself. Moomin takes to his bed, utterly dejected, but Snorkmaiden manages to bring him out of his gloom by showing him something very, very special.

For no special reason Moomin wakes up in the middle of winter and can't go back to sleep. This is quite unheard-of. He is unable to wake the others, and finally, shivering, he makes his way outside into the bleak, unfamiliar whiteness. He meets Little My, who has woken up even before him, and Too-tick who lives in the bath-house. He meets the invisible mice, who also stays there for winter, and he almost meets the Lady of the Cold, the most fearsome of all winter`s manifestations...

Moomin and Little My have finally settled into their wintry existence, living on Too-ticki's fish soup and Moominmamma's jam, of which there fortunately is an awful lot. One day, Mr. Brisk arrives, a very hearty and jovial person, who likes cold baths and roughing it in igloo's. He is much taken with Sorry-oo, a very timid dog who only dreams of running with the wolves that are nightly heard howling in Lonely Mountains. He considers them his brothers, but unfortunately they don't... Mr. Brisk finally leaves, having consumed the last jar of his (and Moomin's) favorite jam.

Wintering away from bed can't be very good for Moomins, for when spring comes Moomin has a terrible cold, and takes to bed when all the others get up. This year Snufkin is very late and Moomin worries far more than is good for him. Finally Snorkmaiden sets off to try and find Snufkin and bring him back, hoping this would bring about a speedy recovery. Stinky makes a bedside call, and agrees to help Moomin go out to look for Snufkin. Poor Stinky - he learns that when you have a bad reputation good deeds don't really help much.

Once again the very fine weather is boring Moominpappa to tears and this time he decides to take the whole family with him and sail for a lighthouse on a small island, not bigger than a fly-speck on the chart. Loaded down they set off and arrive next morning after a harrowing experience with a ghost-ship during the night. They meet a small boat with a man and a boy fishing, but when they get to the lighthouse it is empty, thick with dust and the beacon has gone out. What has happened?

The Moomin's first night in the abandoned lighthouse is haunted by ghosts from the mysterious ghost ship, who finally take off. One of their group is left behind, and the Moomins have to build a raft for it to sail away on. Moominpappa is in vain trying to light the beacon in the lighthouse and they all try to unravel the mystery with the absent keeper. It is finally solved with the help of the small boy, Toft, from the fishing boat, and when the Moomins sail back to Moominvalley they see the lighthouse lit for the first time.

One day, Moominpappa gets a very rare thing, a letter! It is from Aunt Jane, a stinkingly rich relative of whom Moominpappa is rather scared. She is great on duty, and particularly on one's duty to money, so Moominpappa packs a knapsack and flees before she arrives. And very wisely, too, for she wants Moominpappa to look after her gold doubloons when she gets too old! There are, however, those in Moominvalley who need gold for their pet projects - and those who need gold just because they like it.