Sugiani, a black-market racketeer in London, following World War II, is amassing a vast fortune until Linda Medbury, an American newspaper reporter, learns about him and his operation. She wages a crusade against Sugiani, and enlists the aid of her fiancée, 'Jumbo' Hyde, a former British Commando captain. Sugiania tries to buy her off but fails, and then threatens her life. Linda and Hyde get a gymnasium operator to lend them some fighter to storm Sugiani's headquarters.