TNG Season 5 Episode 25: The Inner Light

Captain Picard is ensnared by an alien probe which as far as the rest of the crew is aware, forces him unconscious. They are unaware that another man’s life is being experienced by Jean-Luc, which we the viewer get to experience with him.
Patrick Stewart excels (as he often does) in a great bit of science fiction that won a Hugo award and was nominated for an Emmy. Jay Chattaway’s score for this one is also unforgettable.

Plot

On stardate 45944.1, the Enterprise-D finishes a magnetic wave survey of the Parvenium system and finds an unknown probe. The device rapidly scans the ship and directs an energy beam at Captain Picard, who wakes up to find himself on Kataan, a non-Federation planet. His wife, Eline, tells Picard that he is Kamin, an iron weaver recovering from a fever. Picard speaks of his life on the Enterprise but Eline and their close friend Batai try to convince Picard that his memories were only dreams and incorporate him into their society as Kamin. Picard begins living his life as Kamin in his village, Ressik, having children with Eline and learning to play the flute. Kamin spends much time outdoors and with his Dobsonian telescope studying nature. As years pass, he begins to notice that the drought is caused by increased radiation from the planet's sun. He sends reports to the planet's leaders, who seem to ignore his concerns.
On Enterprise, the crew continues attempts to revive Picard. They try to block the influence of the probe but Picard nearly dies, so they are forced to let it continue. They trace the rocket's trajectory to a system whose sun went nova 1,000 years before, rendering life extinct in the system. Years pass and Kamin outlives Eline and Batai. Kamin and his daughter Meribor continue their study of the drought. They find that it is not temporary; the extinction of life on the planet is inevitable. Kamin confronts a government official who privately admits to him that they already know this but keep it secret to avoid panic. The official gravely points out to Kamin that they have only recently launched artificial satellites using primitive rockets: their race simply does not possess the technology to evacuate people before their planet is rendered uninhabitable.
One day, while playing with his grandson, Kamin is summoned by his adult children to watch the launch of a rocket, which everyone seems to know about except him. As he walks outside into the glaring nova light, Kamin sees Eline and Batai, as young as when he first saw them. They explain that he has already seen the rocket, just before he came there. Knowing that their planet was doomed, the planet's leaders placed memories of their society into a probe and launched it into space, in the hope that it would find someone who could tell others about their species. Picard realizes the context: "Oh, it's me, isn't it?", he says, "I'm the someone... I'm the one it finds", realizing that Kamin was the avatar they chose to represent their race.
Picard wakes up on the bridge of the Enterprise to discover that while he perceived many decades to have transpired, only 25 minutes have passed. The probe terminates and is brought aboard the Enterprise. Inside, the crew finds a small box. Riker gives the box to Picard, who opens it to find Kamin's flute. Picard, now adept at the instrument, plays a melody he learned during his life as Kamin.