ends up in conflict with a Romulan vessel, with both spaceships being disabled by an alien computer virus. "Contagion" was the first episode in the Star Trek franchise in which the Romulan ship was given a name, in this case the Haakona. In the third-season episode "The Enemy", written by David Kemper and Michael Piller and first screened in November 1989, the Enterprise-D is depicted rescuing a crashed Romulan ship. The episode introduced the Romulan character Tomalak, played by Andreas Katsulas, who would reappear in three further Next Generation episodes. It also further established the idea of a significant enmity between the Romulans and the Klingons, with the Enterprises Klingon officer, Worf (Michael Dorn), refusing to donate blood to save the life of an injured Romulan; the scriptwriters had debated whether to include this, with Dorn initially reticent. Three episodes later, in "The Defector", written by Ronald D. Moore and first screened in January 1990, a Romulan admiral is presented as seeking to defect to the Federation. The episode is the first in the franchise to include images of Romulus itself and introduced the design of a Romulan scout vessel. "The Defector" also includes a reference to the Battle of Cheron, an incident in the 22nd century Earth-Romulan War that was previously mentioned in "Balance of Terror". Deep Space Nine and Voyager For "The Search", the opening two-part episode of the third season of Star Trek: Deep Space Nine, a Romulan link was introduced. The episode, which was written by Ira Steven Behr, Robert Hewitt Wolfe, and Ronald D. Moore, featured the introduction of a new Starfleet ship, the USS Defiant; the scriptwriters included the idea that it had been equipped with a cloaking device by the Romulans in return for intelligence that the Federation gathered on another alien power, the Dominion. A Romulan character, T'Rul (Martha Hackett), was included to oversee the device's use aboard the Defiant. The show's writers had initially planned on including T'Rul as a permanent fixture on the show but decided that she did not offer enough potential for new storylines. The Romulans were reused later that season in "Visionary", where they are presented as attempting to destroy the Deep Space Nine space station as part of their plan to collapse the nearby wormhole and thus prevent a Dominion invasion of the Alpha Quadrant, the region of space where both the Federation and Romulans reside.