Written by Ira Steven Behr, Richard Manning, Hans Beimler, & Ronald D. Moore (story by Trent Christopher Ganino & Eric A. Stillwell)
Directed by David Carson
Season 3, Episode 15
Original air date: February 19, 1990
Star date: 43625.2
The Enterprise-D runs across an anomaly that may or may not be there. While they try to sort through their confusing, contradictory sensor readings, something emerges… As another ship crosses the threshold, everything and everyone shifts on the Enterprise-D: Their uniforms now have high collars, belts with phasers, and black cuffs. Nothing gets by Guinan; in the suddenly bustling Ten Forward, the wise and cryptic bartender notes, “This isn’t right. It’s changed.” The mystery deepens: On the now thematically darker Bridge, Worf has been replaced at tactical by an old face, Lt. Tasha Yar, who reports that the other vessel is a Federation starship, registry NCC-1701… C: U.S.S. Enterprise.