The second season of the American science fiction television series Star Trek: Enterprise commenced airing on UPN in the United States on September 18, 2002 and concluded on May 21, 2003 after 26 episodes. Set in the 22nd century, the series follows the adventures of the first Starfleet starship Enterprise, registration NX-01. The second season saw the series continue a concentration on stand-alone episodes as seen in the debut season, but the decision was made to start an ongoing story-arc to run into the third season with the second season finale episode "The Expanse". The second season also saw the return of executive producer Rick Berman to writing duties after he had been working on the film Star Trek: Nemesis.