The crew loses its memory and is tricked into a war.
An alien probe scans the Enterprise, and the entire crew loses its memory, with no one remembering who they are or what they are doing. Working from limited information, they learn that they are caught up in a long war between two peoples, the Lysians and the Satarrans, and they are asked to take part.
Riker and the crew find themselves in a strange situation, following orders without knowing why. The story is a puzzle that uses the amnesia plot to explore questions of duty and identity. The truth behind the war turns out to be a manipulation, and the story ends with a consequential decision.