Richard Castillo Richard Castillo was a male Human Starfleet officer in the 24th century . By 2344 , he attained the rank of lieutenant junior grade . In 2344 , he served as a helmsman aboard the under the command of Captain Rachel Garrett . In that year , the " Enterprise " - C responded to a distress call from the Klingon outpost at Narendra III , which was under attack by four Romulan Warbird s . Castillo was on the bridge during the firefight and survived as the " Enterprise " - C was badly damaged and drifted through a temporal rift , arriving in the year 2366 . He was rescued by the crew of the ship ' s immediate successor , the , which was nearby the rift at that time . The " Enterprise " - D immediately started repairs , with Castillo acting as liaison while Garrett recovered in sickbay . Captain Jean - Luc Picard informed them that the Federation was now at war with the Klingon Empire , and was on the brink of defeat . It was eventually determined that the " Enterprise " - C ' s journey through the rift had resulted in the creation of this alternate timeline , and that , if they wished to restore the proper flow of history , the " Enterprise " - C would have to return through the rift , in the middle of the battle with the Romulans . Despite certain death , Castillo , among many of the crew , agreed that they should return . As the crew of the " Enterprise " - D assisted their counterparts in making repairs , Castillo made the acquaintance of Tasha Yar , the " Enterprise " - D ' s chief tactical officer . She taught him about the advances made during their time , what life was like , and they became close . Castillo having to leave caused a certain amount of distress for both Yar and himself , but they both knew what he had to do . Before the " Enterprise " - C could depart , however , both ships came under attack by a Klingon Bird - of - Prey , resulting in Garrett ' s death . As the highest - ranking crewmember left alive , Castillo took command of the " Enterprise " - C , and prepared to take the ship back through the rift . He was surprised when Yar decided to join him and his crew , having learned that she had died a meaningless death in the other timeline . However , he welcomed her and put her on tactical . Together , they were able to take the ship through the rift and were successful in repairing the timeline . ( ) Appendices . Background information . Richard Castillo was played by Christopher McDonald . The final draft script of " Yesterday ' s Enterprise " described Richard Castillo thus ; " " Castillo is ruggedly handsome , with jet black hair and fiery eyes . " " The costume for Castillo included three five - year service pins , meaning that Castillo had been in Starfleet since at least 2329 . While he identified himself in dialogue as the " Enterprise " - Cs helmsman , his replacement was order to take the conn , suggesting that he might have actually held the position of flight controller . Apocrypha . In the " Star Trek Online " mission " Temporal Ambassador " , it is revealed that the " Enterprise " - D ' s battle with the Klingons in caused the " Enterprise " - C to emerge from the temporal rift in the Azure Nebula in 2409 , rather than Narendra III in 2344 . The alternate timeline remains in place , and the Federation has fallen to the Klingon Empire ( which in turn fell to the Dominion years later ) . The " Enterprise " and her crew - including Castillo - are captured by the Tholian Assembly and held aboard a base in the Azure Nebula , where the player must help them escape and reach the temporal rift so they can return to 2344 .