When the Enterprise is assigned to observe Earth's history in 1968, suddenly it intercepts a transporter beam which originates at least a thousand light-years from Earth, bringing aboard a humanoid alien 'agent Gary Seven' holding a black cat called Isis, who warns them to step back and let him go to accomplish his mission to save Earth; initially phaser-struck down, he manages to beam himself away, actually on a mission to prevent a nuclear rocket being launched at McKinley base because earth is socio-politically not ready for its technological progress. He assumes a classified identity to override a powerful computer, and mistakes the wrong girl, Miss Lincoln, for another agent; the computer reports both other agents he seeks are deceased in an accident. Meanwhile Kirk and Spock beam down to investigate if the alien isn't hostile, realizing the risk of changing their own past. When they get on his trail, the girl sees Spock's ears, calls the police and Seven gets away; they must ... Written by
Did You Know?
When Kirk addresses the crew over the ship's intercom, the first reaction shot among the crew shows Mr. Leslie, wearing a gold officer's tunic, walking through the corridor with Lieutenant Brent. However, the second reaction shot of the same speech shows him in Engineering, wearing a red jumpsuit. See more
Captain James T. Kirk
Captain's log. Using the light speed breakaway factor, the Enterprise has moved back through time to the 20th century. We are now in extended orbit around Earth, using our ship's deflector shields to remain unobserved. Our mission - historical research. We are monitoring Earth communications to find out how our planet survived desperate problems in the year... 1968.