In his desire for more independence, Moomintroll pushes Moominmamma away. But he soon becomes jealous when she finds a new outlet for her motherly love.
Sniff learns that friends are far more important than possessions when he tries to make himself rich by defending the Groke in Moominpappa's impromptu court case, and the Hobgoblin finally arrives in Moominvalley.
Moomintroll wants to try to stand on his own two feet and moves into his own place with Snorkmaiden. But is Moomintroll ready to give up the care and comfort of Moominamma and Moominpappa?
Moominpappa is desperate to be the guiding light of his family again, but his efforts to become the new lighthouse keeper and prove that they can thrive on the desolate island only seems to push them further apart.
Undergoing his own island struggle, Moomintroll realizes he must break away from his parents and overcome childish fears to truly make his transition into independence. His parents finally come to terms with their little Moomin growing up.
After making a hasty return to Moominvalley, only to find the Moomin family have gone away, Snufkin accepts that he can't replace them. He must have faith he will see them again one day, and move on.