Star Trek: The Next Generation - Season 3 - Eps 15: Yesterday's Enterprise
Stardate: 43625.2. A rift in the space/time continuum brings the U.S.S. Enterprise - C forward into the 24th Century, and alters the timeline. In this future, the Federation is at war with the Klingons, Tasha Yar is on the bridge, Worf did not join the Federation, and only Guinan's unique perception of reality may restore the timeline.
About Star Trek: The Next Generation

Title: Star Trek: The Next Generation
First Air Date: 1987-09-28
Last Air Date: 1994-05-23
Status: Ended
Rating: 8.364/10 (from 1547 votes)
Language: EN
Seasons: 8
Total Episodes: 176
Network: Syndication
Genres: Sci-Fi & Fantasy, Action & Adventure, Drama, Mystery
Production Companies: Paramount Television, Norway Corporation
Synopsis
Follow the intergalactic adventures of Capt. Jean-Luc Picard and his loyal crew aboard the all-new USS Enterprise NCC-1701D, as they explore new worlds.
Cast

Patrick Stewart
Jean-Luc Picard

Jonathan Frakes
William T. Riker

Brent Spiner
Data

LeVar Burton
Geordi La Forge

Michael Dorn
Worf

Marina Sirtis
Deanna Troi

Gates McFadden
Beverly Crusher