Lemmy Caution is sent by his bosses to Casablanca to investigate the disappearance of two million dollars, which have seemingly vanished into thin air. There he meets Carlotta de la Rue, the eponymous Poison Ivy, whose character is based on a true-life femme fatale nightclub singer. Lemmy soon uncovers a gang of gold smugglers, whose boss might be Rudy Saltierra, Carlotta's boyfriend. She, in turn, may or may not be on Lemmy's side.