It is spring in the valley and the Moomins are ready for adventure Moomintroll and his friends Snufkin and Sniff find the Hobgoblin's top hat, all shiny and new and just waiting to be taken home. They soon realize that his is no ordinary hat; it can turn anything--or anyone--into something else

Before he had a family, Moominpappa led a life of adventure and intrigue. But he's never told his story until now. He has a bad cold, and it's the perfect time to remember his youthful endeavors and to ponder the experiences which have made him the remarkable Moomin he is.

When a flood sweeps through the valley, the Moomins must find a new house. And with typical Moomin good luck, one just happens to be floating by. It looks normal enough, but there are curtains where one wall should be, strange rows of lights, and other odd amenities. Then Moomintroll and the Snork Maiden disappear, and the family realize that the house may hold the answers to more than they ever dreamed.

When Moomintroll learns that a comet will be passing by, he and his friend Sniff travel to the Observatory on the Lonely Mountains to consult the Professors. Along the way, they have many adventures, but the greatest adventure of all awaits them when they learn that the comet is headed straight for their beloved Moominvalley.

Leave Moominvalley? Is it possible? Yes, even the Moomin family need a change of scenery sometimes, so they're off to live in a lighthouse on a tiny island. Here they find space to grow, and to do things they couldn't in their comfortable, cluttered valley home. As they discover their new home, the family also discover surprising, and wonderfully funny, new things about themselves.

Everyone knows the Moomins sleep through the winter. But this year, Moomintroll has woken up early. So while the rest of the family slumber, he decides to visit his favorite summer haunts. But all he finds is this strange white stuff. Even the sun is gone Moomintroll is angry: whoever Winter is, she has some nerve. Determined to discover the truth about this most mysterious of all seasons, Moomintroll goes where no Moomin has gone before.

Now that autumn is turning into winter, a group of unlikely friends--including the Fillyjonk, the Hemulen, and Toft--are waiting in Moominvalley to see the Moomins, for winter doesn't seem right without them. But the Moomins are not at home. So all the visitors settle down to await their return, and oddly enough find themselves warming up to their new life together. For Moominvalley is Moominvalley still, even without the Moomins in it.