After realizing Himmler and Schellenberg have sent Karl Wolff to negotiate with Allen Dulles in neutral Switzerland, Stierlitz—playing on the rivalries between the Nazi plenipotentiaries—succeeds in leaking the details of the negotiations, conducted under the code name Operation Crossword, both to Hitler and to Stalin. The Soviets, now possessing evidence, demand to end those contacts and President Roosevelt must oblige them. Himmler narrowly convinces Hitler it was all merely an attempt to sow distrust between the Allies. On 24 March 1945, Stierlitz, who managed to clear all suspicions against him, returns to his duties. The Red Army is steadily approaching Berlin.