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.