- For other uses, see Enterprise.
In the mirror universe, the ISS Enterprise (registry NCC-1701-A) was a Terran Empire starship, a Constitution-class battle cruiser in service to Starfleet in the late 23rd century. The Enterprise-A was launched as an Enterprise-subclass refit vessel, commissioned as a replacement for the original Constitution-class ISS Enterprise.
In 2293, the Enterprise-A was commanded by Commander Pavel Chekov, when he took the vessel to the Janus Vortex in order to kill Hikaru Sulu for not including him in his plans to take control of the Terran Empire. During the entire exchange, he was unaware of the fact that Sulu and his crew had exchanged places with their primary universe counterparts. During the battle at the vortex, Chekov detonated an antimatter bomb that destroyed Janus Prime before fleeing from Sulu. He later ambushed the ISS Excelsior with several vessels at an abandoned Terran outpost near the border with the Klingon Empire. He stated he did not know what Sulu's plans were but that they were obviously well worth the betrayal of the Terran Empire and asked to be included in them but later attacked the Excelsior. His assault was repelled and he was forced to flee once more from the battle.
Once safe, he was contacted by Imperial Starfleet Command who ordered him to destroy the Excelsior rather than allow it to fall into Klingon hands. Tracking the ship, he confronted them at the Romulan border where he expressed his confusion over his shifting allegiances by aiding the Klingons. His assault was repelled and he was defeated once again at the hands of Sulu. His failure had reached the ears of Imperial Starfleet Command who were less then pleased of his results. He attempted to offer the excuse that Sulu was unpredictable now and that his goals were not known but they informed him not to let his personal relationship with Sulu to jeopardize the Empire. Believing now that Sulu was attempting to unite the Klingon Empire and the Romulan Republic against the Terran Empire, he ambushing Sulu once again on the border of Romulan space with Tholian space, Chekov was defeated and forced to retreat.
However, this was the last failure the Terran Empire was going to accept. They gave him a death sentence as punishment for his actions and sent him on a suicide mission into Tholian space where the ISS Enterprise-A was trapped by Tholian web spinners. Sending a distress signal, his call for help was answered by the Excelsior and by Sulu who managed to drive off the Tholians. When reinforcements arrived, Chekov formed an alliance with Sulu and together they managed to repel the attackers as well as continue the Excelsior's mission to reach Janus Ultima. Once there, he assisted him in fending off the Imperial Starfleet and giving Sulu enough time to enter the Vortex where he was returned to his reality. (TOS video game: Shattered Universe)