An ordinary British couple vacationing in Switzerland suddenly find themselves embroiled in a case of international intrigue when their daughter is kidnapped by spies plotting a political assassination. This fleet and gripping early thriller from the Master of Suspense, Alfred Hitchcock, was the first film the director made after signing to the Gaumont-British Picture Corporation.

It is the height of the Cold War, and ex-thief Harry Palmer, now reluctantly working as a secret agent, has been called in to investigate a strange occurrence among a number of leading scientists. It seems the scientists have been kidnapped, but reappear only days after the kidnapping, brainwashed and useless. During the course of the investigation, a tape is uncovered with the word "Ipcress" on it.