Lieutenant Hikaru Sulu was the security chief aboard the Starfleet starship ISS Enterprise under Captain James T. Kirk. Sulu had a scar on his face from unknown reasons and had an infatuation with the ship's communications officer, Lieutenant Nyota Uhura.
In 2267, four crewmembers of the USS Enterprise crossed over from the mirror universe during a transporter malfunction while attempting to transport through an ion storm. In their attempt to escape, it was the mission of Lieutenant Uhura to distract Sulu from his security display, which she was successful in manipulating.
A fight later broke out in sickbay as the four crewmen approached the final stage of their escape. Sulu arrived with a security squad and had previously warned Spock that if the Vulcan was not able to command the ship, he would take command. Sulu would, in turn, be defeated when the "captain's woman", Marlena Moreau, utilized the Tantalus field against Sulu's posse, allowing the four members of the USS Enterprise to return back to their universe. (TOS: "Mirror, Mirror")