An engineer and his 5-year old son Rasmus are kidnapped by a group who wants to get their hands on the engineer's latest invention. Three kids become witnesses to the kidnapping and decide to follow the kidnappers to an island and attempt to make a rescue.

A beautiful, wise and fairly fat man at his best age — that’s Karlsson on the Roof. And he isn’t very shy. His door sign says "The world’s best Karlsson". One day he just flew threw the window into Little Brothers bedroom.

About Lena, who loses her family in a tragic car accident and six years later sets out to recreate her family happiness by kidnapping two children and seduce a man, Torben.