Gerald Meldrick (Clark Gable) and Anya von Duren (Rosalind Russell) are a pair of rival jewel thieves at large in India. Both parties are after the same prize, a priceless diamond owned by the Duchess of Beltravers (Jessie Ralph). To inveigle their way into the Duchess' confidence, Gerald poses as a Lloyd's of London detective, while Anya pretends to be an Aristocracy (class). After working at cross purposes, they decide to team up, keeping one step ahead of a diligent police inspector (Matthew Boulton) and mercenary freighter captain Chang (Peter Lorre).