Neale Gordon and Pedro Lake, commercial pilots who fly the hump between Chungking and Calcutta learn, when they reach Calcutta, that their pal, Bill Cunningham, has been murdered. Neales investigation leads him to the Chalgani Club, run by Eric Lasser. Marina Tanov, the club's Russian singer, in love with Neale, tells him that Bill was engaged to an American girl, Virginia Moore. Neale seeks out Virginia, who admits that Bill gave her the $10,000 necklace she is wearing. Knowing that Bill never had that kind of money, Neale checks up. He learns that Bill had actually bought and paid for it. Neale and Virginia are having a drink at the bar when Pedro shows Neale a valuable star-sapphire which he found in the hangar. The pilots then realize they have stumbled onto a smuggling racket. Neale is convinced that Virginia is not involved.