Visiting Berlin headquarters in preparation for a high level U.N.C.L.E. conference, ""Summit Five,"" Solo finds agent Heinz Newman (Don Chastin) mysteriously murdered. Illya goes to Berlin, as does Harry Beldon (Albert Dekker), one of Waverly's counterparts in Section 1. Beldon suspects that either Solo or Gerald Struthers (Lloyd Bochner) committed the murder, while Illya suspects Beldon's secretary Helga Deniken (Suzanne Cramer), but Beldon himself turns out to be the traitor, and he plans to kill Waverly at the conference.

Mr. Webb (Mark Richman), a THRUSH agent, and Margitta Kingsley (Eleanor Parker), the wife of U.N.C.L.E. agent Robert Kingsley (Barry Sullivan), plot to steal a docility gas from General Maximilian Harmon (Leslie Nielson), who has kidnapped Professor David Garrow (Dan O'Herlihy) and his son Steve (Tony Bill). Harmon and a group of scientists consider themselves the ""Seven Intellectual Wonders of the World"" and, with the gas and the troops, plan to take over control of the world and ensure peace.

Mr. Webb (Mark Richman), a THRUSH agent, and Margitta Kingsley (Eleanor Parker), the wife of U.N.C.L.E. agent Robert Kingsley (Barry Sullivan), plot to steal a docility gas from General Maximilian Harmon (Leslie Nielson), who has kidnapped Professor David Garrow (Dan O'Herlihy) and his son Steve (Tony Bill). Harmon and a group of scientists consider themselves the ""Seven Intellectual Wonders of the World"" and, with the gas and the troops, plan to take over control of the world and ensure peace.