Stardate: 46915.2. Riker discovers that eight years ago, an exact clone of him was created when he beamed through a planet's surface while returning to his starship. This clone, named Thomas Riker, has secretly remained on the planet for the past eight years, and still has romantic feelings for Troi.
Stardate: 46682.4. The crew evacuates the Enterprise when the ship needs to be cleaned of particles that have built up over the ship's hull. However, Picard accidentally stumbles over a terrorist group who plan on destroying the ship. He only has a short time to stop their attempts before the ship is swept by a beam of radiation to remove the particles that is lethal to all forms of life.
Stardate: 46154.2. Members of the crew are secretly abducted from the Enterprise to be used in bizarre experiments where they are dismembered and re-assembled without anyone's knowledge - including their own. The only signs that anything is wrong is a strange form of tiredness and no recollection of having slept well the night before.