Spring is coming to Moominvalley. The Moomin family wakes up from their hibernation. Moomin, Snuffle and Mumrick find a top hat that soon turns out to be a magician's hat. Small clouds emerge from eggshells. Moomin, Sniffle and the Snork Maiden enthusiastically ride on the flying little clouds.

Moomin, Snuffle, Snorkmaiden and Mumrick are playing blind man's buff in Moomin House. Moomin hides in the magic hat and is turned into a gnome. He pretends to be the King of California and gets into a fight with Schnüferl, which only Mama can settle. She recognizes her Moomin.

Moomin catches an ant lion and wants to test the magic cylinder on it. He weighs down the hat with Papa's dictionary. Words are running around the house. Because mum has to clean, dad finally wants to get rid of the hat.

Dad doesn't want the magic hat in the house anymore. The cylinder lands in the river. Where the hat has fallen, strange things happen: the fish turn into canaries, and the water turns into delicious raspberry juice.

Mom is doing a big cleaning and accidentally throws seeds into the cylinder. During the nap, the Moominhouse turns into a jungle. Moomin, Mumrick and Snuffle have fun with it. But then you have to clean up.

It's summer in Moominvalley. Nervous new guests Fitslan and Totslan startle the Moomins with news that the terrible Mora is on her way to the valley. All residents barricade themselves in their dwellings. The next morning, the Mora sweeps over the Moomin Valley with hoarfrost.

On a summer's day, the terrible Mora appears and demands the contents of Fitslan and Totslan's suitcase. A court hearing will be held. Mom uses the magician's hat and turns a handful of cherries into sparkling jewels. The mora depart with their loot.

It is autumn. Mumrick is leaving and won't be back until spring. Moomin is very sad about this. Totslan and Fitslan try to cheer him up and show him the secret of the suitcase: a dazzling ruby. Mum, on the other hand, is unlucky: she loses her handbag.

Everyone is still looking for Mama's handbag. The guests invited to the annual autumn festival also help out. The solution to the riddle: Totslan and Fitslan borrowed the bag and are finally returning it. The autumn garden party can begin.

Totslan and Fitslan show off their red ruby ​​to all guests at the Autumn Festival. The gem shines so intensely that the magician gets his attention from the moon. He arrives and tries to buy the ruby. But the wights are unyielding. The spell is easily distracted and enjoys partying.

The fall garden party is in full swing. The magician grants everyone a wish. Moomin has his friend Mumrick send a tasty greeting, Mom wishes her Moomin no craving and Dad gets a book cover. Only the snork lady is dissatisfied with her new eyes.

The festival lasts until the morning hours. The magic gifts all guests generously. Totslan and Fitslan decide to give the magician the red ruby. The magician happily makes his way home. The other guests also say goodbye. The fall garden party is over.

Dad wants to go on a sea voyage. So the Moomin family sails to one of the uninhabited islands off the coast. On its research tour, the Hemul encounters Hatiflaken. The strange little creatures can become electrically charged. They scare the Hemul. Mumrick helps drive out the Hatiflaks.

An upcoming storm prevents the journey home. The Moomin family seeks shelter in a tent. At night the Hatiflaken come and get their barometer from the Hemul. In the commotion, the tent collapses and the Moomins spend an exciting night outdoors.

The sun is shining again the day after the storm. Schnüferl encourages a treasure hunt. He himself finds gold and a cork belt, Moomin finds a snow globe and the Snork Maiden comes across a wooden figure. Together they build a raft to take their treasures with them.

Little My brings the invisible girl Ninni to the Moomins. They should help to cure Ninni of her shyness. All behave in a good-natured, caring and loving manner. Ninni is slowly gaining confidence. When she is not scolded for a mishap, Ninni finally becomes visible.

Hemul wakes the Moomins from their hibernation. They should celebrate Christmas Eve. The ignorant Moomin family quickly learns what Christmas is all about. They decorate a tree, get presents and invite guests.

Winter in Moominvalley. Moomin wakes up from hibernation and finds it difficult to find his way in the changed winter world. He meets the boy Too-Ticky, who has set up shop in Papa's bathhouse with his invisible mice. Moomin and Too-Ticky become friends.

The little girl My enjoys the snow to the fullest. When she gets hungry, she cheekily gets everything she needs from the Moominhouse. Moomin wakes up and is very shocked about the theft. Then he gets to know My.

Too-Ticky, Moomin and My expect the freezing cold and carefully prepare for it. Too-Ticky knows that anyone who looks the terrible Lady of the Cold in the eyes will freeze to death. In the early morning she actually moves through the Moomin Valley.

The winter lasts. To lure out the sun, Too-Ticky and Moomin collect fuel and light a huge fire. The frozen Mora appears, frightens all the valley dwellers and tries to warm up by the fire. The next morning, Moomin is happy about the first rays of sunshine.

Through Too-Ticky, Moomin meets a troll. He can't believe that his ancestors should have looked like that. A look at the family album is also not very revealing. But the troll's behavior provides a clue.

The Hemul as a new winter guest impresses everyone with its sportiness. My competes with the experienced skier and does not cut a bad figure. Moomin has to try too, but he's less successful.

The little dog Sorry-oo comes to Moominvalley in search of his brothers, the wolves. Hemul tries to win his friendship, but Sorry-oo rejects him. He is looking for his brothers. When he finds the wolves, he is in great danger.

Winter is over. The winter guests leave Moominvalley. While skating, little My breaks into the thawing ice. Who can save her?