Lilly Borchert has big plans after graduating from high school and joins the navy as a medical officer to travel the world and prepare for her aspirations to study medicine. But the rules are tough and the nights are short. She finds it hard to make friends in the close-knit crew under Captain Krug. Cadet Klara in particular makes life difficult for her. Lilly records her ordeals, which are accompanied by sleep deprivation and abdominal pain, in a diary. She crosses off the days that separate her from a reunion with her family. One night, when Lilly takes up the lookout post, a tragic accident occurs in which she goes overboard. The search for her in the icy waves is unsuccessful, but she cannot be rescued. What happened to the young woman and how could it come to this?