Katrin Wiedemann is on the verge of becoming a school principal. All she has to do is give birth to her third child and then she can start immediately after maternity leave. Katrin has no doubt that, as an experienced mother, she can juggle her child and her career. Especially because her husband Philipp has promised to take all of her parental leave. Unfortunately, the school istration has a different opinion and, after the turbulent birth of little Isalie, asks Philipp of all people to take over as heaster for the time being. In the mistaken belief that he is doing Katrin a favor, he agrees.