Set in the City of Light, this crime melodrama chronicles the attempts of a US drug agent to stop a major drug-lord. Though the agent realizes his three predecessors have been assassinated, and that the French government doesn't necessarily approve of the Yank's harassment of a French citizen, he is determined to succeed. Then a Parisian cop quietly suggests that Anthony Quinn himself hire an assassin to kill the drug lord. He thinks about it long and hard, before agreeing to it. Later he is shocked to learn that the assassin is an old war buddy. The hit man then works overtime to cozy up to the criminal and earn his trust. While he is doing that, the agent learns that events have changed and he must capture the drug lord alive. Unfortunately, he must first find a way to call off the professional killer before it is too late.