In West Berlin at the height of the Cold War, British spy Eberlin (Laurence Harvey) is tasked with the dangerous assignment of finding and assassinating the treacherous KGB agent Krasnevin, who has killed many undercover British agents. He's given a new partner, Gatiss (Tom Courtenay), to help eliminate the deadly Russian. What neither his bosses nor his partner know, however, is that Eberlin himself is Krasnevin, a double agent whose secret identity his Moscow bosses don't want compromised.