Episode Title: "ASSIGNMENT: EARTH"
Production Number: 55
Original Air Date: 03-29-68
The United Space Ship Enterprise has used the light speed breakaway factor to travel back to Earth in the Twentieth Century, on a mission of historical research in the year 1968. While monitoring Earth communications, the Enterprise intercepts a transporter beam from one thousand light-years away.
A man calling himself Gary Seven materializes aboard the Enterprise with a black cat named Isis, and he claims to be a human from the Twentieth Century who was living on an advanced alien planet and is beaming to Earth on an important mission. Mister Seven has knowledge of the future, and is able to resist Commander Spock's Vulcan neck pinch. Captain Kirk has him locked in security confinement until Seven's identity can be verified, but Gary Seven uses advanced alien devices to escape and beam down to Earth.
At this critical time in Earth history, there will be an important assassination, a dangerous government coup in Asia, and the United States will launch an orbital nuclear warhead platform, countering a similar launch by other powers.
The man code-named Gary Seven is Supervisor 194, and uses an advanced Beta-Five computer in a secret office on Earth to search for two missing agents, who were descended from human ancestors taken from Earth six thousand years ago and products of generations of training for this mission. The agents are there to prevent Earth from destroying itself with its weapons technology before it can develop into a peaceful society.
Gary Seven learns that Agents 347 and 201 were killed in an automobile accident on Highway 949 ten miles north of McKinley Rocket Base, so he must assume their mission, with help from Roberta Lincoln, a local woman hired as a secretary by the agents.
Captain Kirk and Commander Spock track Gary Seven to McKinley Rocket Base, where the nuclear warhead platform is about to be launched. Gary Seven is not able to complete his sabotage of the rocket before the Enterprise tries to beam him aboard, but Seven convinces Captain Kirk to let him destroy the rocket manually in orbit before it causes a nuclear explosion on Earth. The malfunctioning sub-orbital warhead that explodes in space leads to an international agreement against developing other such weapons in the future.
Kirk and Spock return to the Enterprise, leaving Gary Seven and Roberta Lincoln to continue their adventures on Earth.
Factoid: Earth's launching of nuclear weapons platforms is similar to the situation that almost destroyed planet Omicron Four.
Guest Characters: *Supervisor 194 'Gary Seven', *Roberta Lincoln, Lt. Leslie
KEY: [brackets]=illusions *star=first appearance