Cookie manufacturer Bertram Dinkler with his old-fashioned know-it-all attitude triggers an unexpected fighting spirit not in the teenagers, but in single mother Stefanie Eckhoff. Stefanie challenges Bertram. She wants him to do a sports badge and try to do better than her. Right from the first training session, the rivals realize that they may have gone a little too far. Fortunately, their stubbornness helps both of them to unleash unexpected energy.