Karlsson's grandmother is the world's best racing driver and Karlsson is not so bad either. Kaxige Kirre challenges Karlsson in a box car race. Now it is up to Karlsson and Lillebror to build a really fast car so that they can give Kirre what he can stand. Little brother has made a kite at school that he wants to test fly with Bosse. Just this day, it blows a lot so the dragon wears itself out and sticks out into the sky.

Svante is a young boy who lives with his family in a Stockholm apartment. One day he meets Karlsson, a chubby little man in the prime of his life, who can fly using a propeller on his back and who lives in his little house on the roof.