Is it possible? Can the Moomins ever leave their Valley? Their beloved home? Yet: even a family like this needs a change of scenery at some point. So together, they leave and go to live on a small island in the middle of the sea.

On an island where there is nothing but a lighthouse. In their new home, they will struggle, settle in, and do things they could not and did not dare to do in the Valley. While exploring and discovering their new home, the family also discovers many unexpected things about themselves.

Moomin will get to know the Snork Maiden better, Mamma Moomin will start painting, Papa Moomin will study the mysteries of the sea, and Little My will unravel the mystery of the missing lighthouse keeper.

The Moomin family, with their many and varied relatives and friends who are occasionally hosted in the House in the Valley, are among the most significant characters that children's literature has to offer. Their stories, written and illustrated by Tove Jansson, unfold in a magical world where creatures of imagination live - but with such recognizable human traits! Like all great works of children's literature, they are not only for children, but for readers of all ages.