ST:TNG:82 - "Future Imperfect" (Stardate: 44286.5) - this is the 8th episode of the 4th season of Star Trek: The Next Generation.
In this Riker episode, when he leads an away team to investigate a suspected Romulan base near the Neuteral Zone, he and the others are overcome by a poisonous gas. When he wakes up, he finds out it is 16 years later with no memory of those years! 16 years into the future, he is now Captain of the Enterprise, with Picard now an Ambassador. Geordi now has no visor, Troi is no longer counselor of the Enterprise and now wears a blue commander uniform (which foreshadows her wearing it in the latter seasons), peace is about to be made with the Romulans (through Ambassador Tomalak - played again by the late Andreas Katsulas) and there is a Ferengi at the Enterprise helm! However, things are not what they seem to be as Riker finds out slowly but surely.
Trivia note: Patti Yasutake makes her first of many appearances as Nurse Alyssa Ogawa. We see Riker play the trombone (not too perfectly) at his birthday party. And Carolyn McCormick returns as Minuet.
Also, it's interesting to note that 12 years after this episode (which takes place in our 1990), the Enterprise helped a Romulan vessel in its distress, which paved the way for the peace talks now. The same thing happened in Star Trek: Nemesis (2002) when the Enterprise and the Romulans worked together to stop Shinzon - exactly 12 years since this 1990 episode!
In this Riker episode, when he leads an away team to investigate a suspected Romulan base near the Neuteral Zone, he and the others are overcome by a poisonous gas. When he wakes up, he finds out it is 16 years later with no memory of those years! 16 years into the future, he is now Captain of the Enterprise, with Picard now an Ambassador. Geordi now has no visor, Troi is no longer counselor of the Enterprise and now wears a blue commander uniform (which foreshadows her wearing it in the latter seasons), peace is about to be made with the Romulans (through Ambassador Tomalak - played again by the late Andreas Katsulas) and there is a Ferengi at the Enterprise helm! However, things are not what they seem to be as Riker finds out slowly but surely.
Trivia note: Patti Yasutake makes her first of many appearances as Nurse Alyssa Ogawa. We see Riker play the trombone (not too perfectly) at his birthday party. And Carolyn McCormick returns as Minuet.
Also, it's interesting to note that 12 years after this episode (which takes place in our 1990), the Enterprise helped a Romulan vessel in its distress, which paved the way for the peace talks now. The same thing happened in Star Trek: Nemesis (2002) when the Enterprise and the Romulans worked together to stop Shinzon - exactly 12 years since this 1990 episode!