Tin und sein Vater besuchen das verbotene Meer, wo ein riesiger Krake seinen Vater entführt. Tin springt hinterher und wird zum Meermenschen. Auf der Suche nach seinem Vater wird er von Seeungeheuern angegriffen, aber von George, einem leuchtenden Wal, gerettet. Gemeinsam wollen sie Tins Vater befreien und die Meere retten.
Thore's seventh birthday takes a turn when the Bandalord, the universe's nastiest alien, steals his presents and kidnaps his best friend Luk. Uniquely, Thore is the only one who remembers birthdays. With the help of Pustapala from Schnuffpuff, he bravely confronts the Bandalord to save his friend and restore birthdays.
When Tin visits the forbidden sea with his father, a giant octopus pulls his father underwater. Tin jumps in and transforms into a merman. He faces sea monsters but is rescued by George, a shining whale. George reveals that Tin's family are the keepers of the seas, and they must rescue his father from Uncle Zerkas.