Roos Hartman is a young doctor who lives with her son in a large apartment complex. When a fellow tenant is brutally murdered, the police and Hartman's friends suspect her mysterious neighbour, Eric Coenen. As she becomes romantically involved with Coenen, she doubts he would commit such a crime, but soon she begins to investigate the case further and discovers some startling facts relating to his involvement..

An unlikely friendship blossoms between Elsa, a preppy, idle, spoiled blond who calls herself Gino, and Nina, a wannabe anarchist who plots with three others to blow up an arms factory. Nina is often sour and tempestuous, but with Gino she's spontaneous and funny. Yet the friendship often founders, as the feckless Gino spoils Nina's frequent and demanding plans. They decide to rob Gino's rich uncle to pay for bombs and creature comforts, they sneak into a stranger's house, they steal a painting belonging to one of Gino's boyfriends, bombs fail to explode, and Gino costs Nina the trust of her anarchist pals. Then comes the crocodile test, the ultimate for any friendship.