Marcel (Charles Boyer) is set to perpetrate an art swap on stingy businessman Amos Cavanaugh (Broderick Crawford). But Cavanaugh has put a twist to the con by unexpectedly donating his Rembrandt to the SF Art Museum. Fake copies cloud the investigation while they search for the real Rembrandt. The museum and Cavanaugh wish to work the dealings on their own, keeping the press and the police out of it; when several step forward claiming they have the original and asking for a ransom. Can Marcel and the Rouges make everything right by finding and delivering the real Rembrandt to the museum (as promised by Cavanaugh) and then seeing that cheaters don't prosper in this complex double and triple cross.