On the roof of the house at Krumme Gasse 7, two birch trees suddenly grow in a magical way from a small patch of moss. And as something is already there, more is added: Slowly, a real rooftop garden begins to take shape. Henne, a roofer with a slight roof issue, and Henrike, a twelve-year-old girl, carry soil, bring plants, and tend to the little green space. They are supported by two chimney sweeps, a mysterious giant with an iron hand, a roof wanderer, Henrike's teacher, and various mysterious forces. The duck Ilse builds a nest and hatches her young. Everything seems peaceful, but appearances are deceiving - in the background, Mrs. Hux is working to drive the people off the roof and restore order. She almost succeeds - but where many good forces come together, malice is powerless.