ST:TNG:161 - "Force Of Nature" (Stardate: 47310.2) - this is the 9th episode of the 7th and last season of Star Trek: The Next Generation.
The Enterprise arrives in a area which poses a hazard to warp-driven vessels, searching for the U.S.S. Fleming, a medical transport that disappeared in this region of space. Soon, they discover who the culprit was - two aliens who have been disabling ships in this area to get the Federation to listen to their concerns - that the use of warp drives may be decimating their planet and destroying the fabric of space! A very intriguing "environmental" episode.
Trivia note: Data's cat Spot is seen again, but in this episode and the upcoming "Genesis", he is now a she! Data also tries to train the cat throughout this episode, with varying success.
The Enterprise arrives in a area which poses a hazard to warp-driven vessels, searching for the U.S.S. Fleming, a medical transport that disappeared in this region of space. Soon, they discover who the culprit was - two aliens who have been disabling ships in this area to get the Federation to listen to their concerns - that the use of warp drives may be decimating their planet and destroying the fabric of space! A very intriguing "environmental" episode.
Trivia note: Data's cat Spot is seen again, but in this episode and the upcoming "Genesis", he is now a she! Data also tries to train the cat throughout this episode, with varying success.