Bronson and Remick make an unusual, but intriguing pair in this cold war suspense drama. He plays a KGB agent (with a notable American accent, attributed to his many trips to the U.S.!) who is sent to eliminate a renegade Stalinist who is wreaking havoc on various American military/industrial sites. The renegade (Pleasence) has unearthed a 15 year-old plot that the Soviets had put into place and then abandoned in which 51 agents were brainwashed into believing that they were Americans, but who can be reactivated through verbal command to complete their missions. Once they hear the key phrase (usually delivered to them over the telephone, hence the title), they single-mindedly go about blowing up whatever target was originally intended and then offing themselves. Bronson joins forces with CIA operative Remick, giving her limited information about the mission, but using her resources to reach his ends. The film becomes a sort of cross-country chase as the agent couple fight to either catch up to or stay ahead of Pleasence before he sets off another dormant killing machine. Logic and believability often take a backseat here with the premise itself being a little hard to swallow. However, the acting of the leads and the eeriness of the situation go a long way to cover up the problems with the plot. Bronson is his usual rather silent, tough self, but it works, especially against the more animated and sophisticated Remick. Her character is not always particularly credible, but she adds tastefulness to any film and can always be counted on for good reactions (her eyes captured more light than practically anyone before or since, except maybe Meg Foster.) There are some other decent performances in the film (such as Magee as a weary Russian general) but one that grates is Daly as a know-it-all CIA computer technician. Meant to be comic relief, she winds up more of a distraction and a point of irritation during a lot of her scenes. Pleasence has few lines and isn't in the film a great deal, but manages to ham it up nonetheless with several unintentionally hilarious expressions and loopy disguises. Composer Schifrin provides an effective, Russian-tinged score for the film.
