Smuggler Carnaghan (Spencer Tracy) is let out of prison by government agent Kellar (John Hodiak) on condition that he help John Royer (James Stewart) sneak the entire vitally-needed rubber crop out of Japanese-held Malaya during World War II. They slip into the country and contact Carnaghan's associate, the Dutchman (Sydney Greenstreet), who conveniently recruits a gang of cutthroats for them from customers in his saloon, including Romano (Gilbert Roland). Using money and intimidation, they succeed in purchasing all the available rubber, but eventually the Japanese commander, Colonel Tomura (Richard Loo), gets wind of the scheme. On the last trip to transport the remainder of the cargo to a waiting freighter, Carnaghan smells an ambush, but Royer disregards his warning and is killed by the waiting soldiers. The cynical Carnaghan then turns patriotic and completes the mission.