U.N.C.L.E. agents Napoleon Solo and Illya Kuryakin are sent to the Swiss Alps to find a secret nuclear weapon design but T.H.R.U.S.H. agents kidnap Solo and replace him with a look-alike double.

Thrush captures Napoleon Solo and replaces him with a look-alike to infiltrate U.N.C.L.E. and an operation called "The August Affair". While Solo is being held prisoner, Illya Kuryakin becomes suspicious by the unusual behavior of his friend, and slowly starts to realize what has happened. The real Solo must escape and stop his Thrush double before it's too late. This film is made up from "The Double Affair" (11/17/64) and "The Four Steps Affair" (02/22/65) from the first season of The Man From U.N.C.L.E.—Daniel Bolton