The chairman of the MIT mathematics department, Martin offers John Nash an instructorship at the university in the 1950s. Martin is a “loquacious” mathematician known for luring “young hotshots” to the department. At the height of the McCarthy era during the Cold War (a period in which the aggressively anti-communist U.S. Senator Joseph McCarthy led a committee to weed suspected Communists and Soviet spies out of the U.S.), Martin’s “secret past” as an underground member of the Communist Party in the late 1930s and early 1940s is exposed.