Alfred Redl (Emil Artur Longen), a colonel on the Austrian General Staff, leads an extravagant private life. No one suspects that in reality he is passing information to Russian spies. To obtain further information the Russians station agent Levanzová (Marie Grossová) to him, but Redl resists the temptations of the beautiful woman. Levanzová discovers Redl's passionate letters intended for Lieutenant Dolan (Jirí Sedlácek) . Redl is transferred to Prague and he tries to prevent the lieutenant from marrying. The Russians threaten Redl with making public his letters to Dolan and they force him to give away the plans for an attack in Galicia.