The Mark of Gideon

Plot

On stardate 5423.4, the Federation starship Enterprise arrives at the planet Gideon to begin diplomatic relations and invite the inhabitants to join the Federation. Gideon is reported to be a virtual paradise where the people live incredibly long lives in a nearly germ-free environment.

Upon arrival, however, the Gideon representative, Ambassador Hodin, refuses to allow anyone to beam down to the planet except for Captain Kirk, to whom he gives specific coordinates where to transport. Kirk agrees to beam down and after transport finds himself apparently still aboard the Enterprise. After looking around, he finds, to his surprise, the ship is completely devoid of any crew.

First Officer Spock, on the Enterprise, is informed that the Captain never arrived on the planet; however, Ambassador Hodin refuses to allow a search team to investigate. Spock contacts Admiral Fitzgerald of Starfleet to report Kirk's disappearance and request further instruction; however, Starfleet is bogged down by bureaucratic red tape between Gideon and the Department of Planetary Treaties. Fitzgerald orders Spock to "stand by" for the time being.

Spock knew the coordinates were to send Kirk directly to the Gideon council chamber, so Spock asks to beam a member of the Gideon council up to the Enterprise to test the transporter. Hodin agrees and sends council member Krodak up to the ship, but then remembers that he has already allowed Kirk to transport to the planet and refuses to allow any more Enterprise crew to beam down. Krodak successfully beams back down to the planet, confirming that the transporter is working normally.

Meanwhile, Kirk wanders the deserted Enterprise and then notices a strange bruise on his arm. He eventually runs into a beautiful young woman named Odona. She too, has no idea how she got to the empty Enterprise, so she says, recalling only that she was in an overcrowded auditorium and struggling to breathe. For the moment, Odona is just relieved to have freedom of movement. Kirk insists that she must be from Gideon, but Odona denies any knowledge of the planet.

Kirk learns from Odona that her home planet is severely overpopulated, with crowds of people everywhere and no privacy. To her, the privilege of being alone, even for a moment, is a dream come true. Kirk thinks Odona's beauty is a dream come true, and the two share a passionate kiss. Neither notice the strange ghostly image of a dozen faces appearing on the bridge's view screen behind them.

As Kirk and Odona leave the bridge, Kirk hears a strange sound outside the ship. He goes to a viewport and catches a glimpse of a crowd of people dressed in tight-fitting body suits. The scene quickly fades to a view of normal space and he realizes something is wrong. Kirk confronts Odona about what is going on, but she denies knowing what is happening. She then quickly falls ill, fainting into Kirk's arms.

Kirk carries her to Sickbay, where he encounters Ambassador Hodin, who explains that Kirk is part of a secret experiment on Gideon. Odona is Hodin's daughter, and she has just been infected with Vegan choriomeningitis, a potentially lethal virus that nearly killed Kirk. He is now immune to the microbe, but still carries it in his blood. Hodin's plan is to infect his people with the virus in an attempt to "control" the overpopulation problem caused by the people's long lifespans in a germ-free environment.

Kirk is angered that he has been an unwitting pawn in their plan, and questions why the Gideon people have not tried sterilization or birth control. Hodin explains that the Gideon people have regenerative abilities that have foiled sterilization attempts, and that their people hold love and the ability to create life sacred.

Kirk is also horrified to learn that he must remain behind to supply the virus as needed; however, Kirk believes that Odona can fulfill that role now that she has been infected. Hodin explains that Odona must die from the virus so that she will become a role model for the youth of the world, who will step forward and give up their lives for the benefit of the population.

Meanwhile, Spock becomes anxious to learn what happened to his captain. When he discovers that Kirk's coordinates and the coordinates given to test the transporter do not match, he goes against Starfleet orders and beams down to Kirk's original coordinates. Once there, he finds the false Enterprise that was built to deceive Kirk.

Spock overpowers some guards and finds Kirk and Odona. Hodin tries to stop Spock, but Spock warns him not to interfere since he has just disobeyed Starfleet orders and must now return to resolve the matter. Kirk, Spock and Odona return to the real Enterprise where Chief Medical Officer Dr. McCoy saves Odona's life. Odona still carries the virus but is now immune to it, as Kirk is. Odona is returned to Gideon and Hodin is told she can now supply the virus as needed.