The Enterprise has been thrown three days back in time, after its dramatic escape from the disintegrating planet, Psi 2000, and to make use of the time, they go to check up on a planetary survey team they had left behind exploring. On arriving at the planet, Tlaoli, they discover one group had gone missing while investigating some caves that they suspected were related to the nineteen crashed starships they had located on the planet. Kirk leads a mission to locate the missing group, with McCoy, Uhura and Chekov among the team members. Power drains have been noticed on the planet, so the rescuers have to rely on carbide lamps to find their way. When they try using phaser bursts to illuminate the caves, the temperature starts to drop dramatically, and Chekov slips on the ice and falls into an underground river and Kirk follows him, resulting in the discovery of a section of the caves that appears to have been artificially created, and it is believed that it was probably not underground when it had been created. This leads to the discovery of the missing geologists. While they are trying to find a way out, Kirk and Chekov disappear in what appears to be an alien transporter beam. Chekov is discovered soon afterwards, but he has lost all memory of the past few hours. When they finally find a way up to the surface, they notice footprints which they assume are those of Kirk, heading out away from their camp. Meanwhile, a shuttle has been fitted out with shielding against the energy draining effect. The Enterprise itself had almost been pulled down to the planet before being able to blast itself free – using photon torpedoes. Sulu takes the shielded shuttle down to the surface, and is able to locate the team (now under Uhura’s command). He takes the shuttle out to try to locate Kirk, and indicates that he has seen him, and is returning when an explosion is heard. Uhura suspects that the shuttle ran into the same transporter field they had encountered in the tunnels, and she leads a group back into the tunnels on the assumption that Sulu might have ended up in the same location that Chekov, and apparently Kirk, had reappeared. Meanwhile, Chekov leads a group to try to find Kirk and, when they find him, he is a frightened 14 year old. Uhura’s team find Sulu, but the Sulu they find is about twenty years older, and had been in a war against the Gorn, and had no recollection of a Captain Kirk. [Timeline: Stardate 1704.3, year 2268]