Star Trek: The Next Generation: The Space Between #1: History Lesson

"Captain's Log: Stardate 41590.8.

The Enterprise is in orbit over Tigan, a technologically advanced but traditionally isolationist World... ... which has only recently opened communications with the Federation."

The crew of the Enterprise are responding to a call from the world of Tigan. When Away Team lands on the planet they are lead to believe, they are to meet with Chancellor Lomac. When introduced to the Chancellor, it is not who they expect. They come to find out there is no records of Lomac ever existing. The Away Team, finds this very suspicious and star their investigation.

"There is no record of Chancellor Lomac, or his administration...." - Data

Back on the Enterprise, the ships crew is investigating an strange energy pulse occurring on the surface of Tigan. Out of no where they are attack with a gravimetric wave, pushing them away from the planet at near light speed. Their new destination... the Gamma Quadrant.

"If we don't act soon, we will end up in the Gamma Quadrant..." - Worf

On the surface the Away Team starts looking over the Tigan Central Computer. Data finds out they have been wiping the memories of the entire race and replacing them with new updated information for over the past 200 years. At this point the new Chancellor captures the Away Team, and tries to reprogram Data's memories of his visit on Tigan....

"...Ten times in the last two hundred years, and six in the last decade." - Tasha Yar