Plot summary
Dax and Odo investigate an unusual particle field emanating from a planet in the Gamma Quadrant; they discover the field is coming from a small village's power generator. The village magistrate, Colyus, tells them 22 people have disappeared without a trace in the past few days. Odo and Dax offer to help investigate the disappearances; but the oldest villager, Rurigan, seems unconvinced that the villagers will ever be found.
The next day, Odo interviews Rurigan's granddaughter, Taya, whose mother has disappeared. The two find common ground in that they are both orphans; during the course of their conversation, Taya reveals that the villagers never leave their valley. Rurigan assures Odo that searching beyond the valley would be pointless. Apparently no one has thought about searching beyond the valley or ever considered leaving it.
Taya brings Odo and Dax to the edge of the valley. When Dax leaves the valley, a device from the village vanishes from her hand. Taya reaches past the edge of the valley, and her arm begins to disappear. The three return to the village to share their findings: the entire village, including its citizens, is a hologram created by the reactor's particle field. The reactor has fallen into disrepair and is breaking down, causing the villagers to disappear one by one.
They convince the villagers to let Dax shut down the reactor and repair it before it stops functioning completely. When she does so, the village and all the villagers vanish – except Rurigan. He explains that when an alien empire known as the Dominion arrived on his home planet, he fled to an abandoned planet and recreated the world he had lost; but now he admits that none of it was real. However, Odo argues that Taya and the others are real and deserve a chance to live. Dax and Rurigan repair the reactor, restoring the village, including the missing people. Before he and Dax leave, Odo realizes how close he has grown to Taya, and demonstrates his abilities by morphing into a toy that Taya played with earlier.
Meanwhile, back on Deep Space Nine, Major Kira begins a romance with Vedek Bareil; the bartender Quark had Bareil invited to the station to distract Kira from a criminal operation he was planning, but she sees through the scheme and apprehends Quark's accomplice. Jake Sisko begins taking engineering lessons from Miles O'Brien, but eventually admits to his father that he doesn't want to join Starfleet.
Credits
Adapted from Wikipedia contributors, Shadowplay (Star Trek: Deep Space Nine). Paragraphs and formatting adjusted; illustrations, reference markers, block quotations and non-story material omitted.