The USS Enterprise arrives in Earth's past in the 1960s due to the repercussions of a high-gravity "black star." The spacecraft appears in the Earth's upper atmosphere and is classified as an unidentified flying object by military radar. An F-104 interceptor aircraft with Captain John Christopher (Roger Perry) as its pilot is hurriedly dispatched to identify the craft. Kirk, worried about a potential attack, orders a tractor beam to grasp the airplane, which unfortunately causes it to be torn into pieces. Nevertheless, the pilot is beamed onto the Enterprise just in time.

Initially, owing to his fear that Christopher could disrupt the timeline if sent back to Earth, Kirk decides to keep the pilot with the Enterprise. Nevertheless, after Spock, the Science Officer, finds out that the pilot's unborn son would be an essential part of an upcoming mission to Saturn, Kirk realizes that he must return Christopher to Earth after all.

After the Enterprise crew discovered that Christopher had recorded footage of their voyage, Kirk and Lt. Sulu beamed to the airbase to collect the recordings and other proof of their presence. Unfortunately, an Air Policeman spotted them and, in apprehending Kirk, hit something on his communicator, which set off an alarm, and he was beamed up to the ship. Kirk was arrested once again, while Sulu got away.

Spock, Sulu, and Christopher, who was familiar with the base's design, were beamed down to rescue Kirk. After the landing party took care of the folks protecting Kirk, Christopher seized one of the guns and requested to be abandoned. Spock, who had expected Christopher to attempt something like this, appeared behind him and used a Vulcan nerve pinch to disable him.

Spock and Chief Engineer Scott let Kirk know that they might be able to get away from the situation by utilizing a method called slingshotting around the Sun. However, this tactic is quite dangerous, as the slightest mistake could result in the obliteration of the ship or the crew missing their own time.

Kirk approves the plan, and the Enterprise travels back in time. Christopher is then transported back to his airplane, where he first encountered the Enterprise, guaranteeing that there would be no proof of the ship's existence and completely erasing his recollection of his time on the Enterprise. The same is done with Captain Christopher Subsequently. The Enterprise successfully returns to the 23rd century. The Enterprise is the heroine of this episode, an overdue honor.

Cheers,
Hophead Jon