12-year-old Florian and his beloved dog Lassie live in an idyllic village in the German countryside. When Florian's father loses his job, the family have to move into a small apartment where there are no dogs allowed. Lassie is given away to another family, but Florian and Lassie yearn to be reunited again so Florian sets out on an adventure to find his best friend.

In the not-too-distant future: after a global catastrophe has wiped out nearly all of humanity on Earth, an elite astronaut from Space Colony Kepler must make a decision that will seal the fate of the people on both planets.