During the spring of 1941, Richard Sorge, a Soviet secret agent with the codename Ramsay, learns from the German Ambassador to Japan that Hitler has decided to invade the Soviet Union.

Due to his proximity to the leadership of the German diplomatic mission, Sorge learns that Japan is preparing an attack on the western shore of Lake Hassan in order to test the combat effectiveness of the Soviet army.

The Japanese Major Osaki suspects Sorge of belonging to a spy ring, but Colonel Kawai prevents him from conducting an investigation; Sorge gains access to classified information about upcoming Japanese military operations against the USSR.

Sorge learns from his agents that Japan is preparing an attack on a remote area of Mongolia where Soviet troops are deployed; Sorge skilfully uses the information to attempt to prevent a war between Japan and the USSR.

Germany and the USSR sign a non-aggression pact, but soon afterwards, Ott shows Sorge a telegram that states Germany has invaded Poland; Schlesinger finds incriminating evidence that Sorge has begun an affair with Helma Ott.

One of the Sorge cell members turns out to be an American agent; meanwhile, Ott returns from Berlin with news for Sorge.