In 1933 Berlin and Munich, fifteen-year-olds Katarina and Maria, who have never met, share the same dream: to become nurses who care for all regardless of race, creed, or colour.

They achieve their dreams, but their determination to rise above prejudice brings them into conflict with the authorities and very close to danger of arrest. As a result, they both find themselves sent to the same hospital in France, more for their own safety, where they meet unexpectedly and become firm friends. They look so similar to each other that people often mistake them, which leads them to play tricks on the people they meet.

The nurses find themselves on the Mediterranean Sea, bound for North Africa. Misfortune strikes when their ship, the Meer Königin (Queen of the Sea) strikes a mine and begins to sink. Alone and adrift in a life raft, Katarina and Maria want to help others live, but that will never happen unless they find a way to survive.