The Elysian Kingdom
Summary
The Enterprise is surveying a nebula when its warp drive fails, causing the crew to black out. M'Benga awakens to find the Enterprise interior dressed as the high fantasy setting of Rukiya's favorite book and the crew unwittingly acting out its events in character. Chief engineer Hemmer is the only other crew member aware of the situation, thanks to his telepathic abilities, and they discover that the nebula has its own consciousness comparable to a Boltzmann brain. They find Rukiya and learn the nebula had detected her loneliness and created the fantasy to entertain her. It also cured her disease, but this will not last if they leave the nebula. The nebula offers to preserve Rukiya by converting her into an energy being within the nebula, which M'Benga reluctantly agrees to.
Summary from Wikipedia, CC BY-SA 4.0.
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