A probe gives Picard decades of memories as a man on a dying world.
The Enterprise encounters a mysterious probe that sends a beam of energy to Picard. He loses consciousness, and when he wakes, he is living a new life as Kamin, a man on a planet called Kataan. Over what seems like decades, Kamin builds a family and a life, while on the Enterprise the crew watches his body lying helpless.
The truth is that the probe is a memorial, left behind by a civilization that died long ago and wished to be remembered. The episode is frequently ranked as one of the finest of the entire franchise, and it won a major science-fiction award. The flute that Kamin learns to play becomes a lasting part of Picard's character, appearing in later stories.