After fatally shooting a stalker, Parisian bar-maid Lea must live the life of the title reptile. At the time of the killing she was living with Francis, a much older American ex-con. After committing the murder, the fleeing and frightened Lea is saved by Paris paper boys Jean and Luc. Later she tells her sad story to hard-drinking Moskowitz, a middle-aged cop who secretly desires her. His unrequited love leads to tragedy. Meanwhile, Lea continues living with Francis, but also shacks up with Luc while trying to avoid the jealous cop.