It takes a thief..."Le Chat" ("The Cat"), an infamous thief, has come out of retirement and is again liberating expensive jewelry from wealthy tourists on the FreRch Riviera. Or is it a "copycat" who is stealing fortunes? John Robie thought he had left his larcenous past behind. Once responsible for a string of daring thefts and escapes, he was caught and sent to prison just before the outbreak of World War II. Freed during the German occupation of France, Robie joined the French Resistance and received unofficial amnesty after the war ended. He retired to a simple life in the country where he befriended the local commissaire, Oriol, and tended his gardens. Now it's 1951, and someone has been at work using his old MO. When the police come to arrest him, Robie escapes to Cannes. There, he reconnects with his former comrade Bellini, who convinces Robie to help catch the copycat. Disguised as a pudgy, middle-aged American businessman, Robie scouts the local nightclubs and casinos and tries to outthink the new thief. When he meets Francie Stevens, the daughter of a wealthy tourist, she becomes Robie's unwelcome ally, and together they hatch a dangerous plan to catch the thief at a gala party. But soon they both realize that Robie really is a thief at heart. With Oriol and the police on his trail, will he escape capture? Will the real thief be caught? And will Robie give up the thief?