Six-year-old Louis should stay in Berlin with his aunt Marita while his mother goes to a job interview. Marita is a somewhat grouchy, single and childless career woman who actually doesn't want to take care of Louis, and certainly not visit the zoo with him. While she always chatters in her handy, she leaves him to his own devices which for example are helping homeless people rummaging through trash cans and give his subway ticket to scrounging punks. When his aunt tells him in horror not to talk to strangers anymore, Louis does promptly what he is told, even when a policeman addresses him. Finally, they land in a police station. Marita learns to change her views...