Plot summary
An infant is found in the wreckage of a ship that the bartender Quark (Armin Shimerman) buys as salvage. The boy grows at a phenomenal rate, developing in appearance to an eight-year-old in only a few hours. Dr. Bashir (Alexander Siddig) determines that the child is the result of genetic engineering. As the boy continues to develop, his aggression, evolving appearance, and reverence for security chief Odo (a rogue Changeling) reveal that he is Jem'Hadar.
Odo (René Auberjonois) convinces Commander Sisko (Avery Brooks) that the boy should not be sent to Starfleet Command as a specimen to be studied. He believes that he can control the boy because Jem'Hadar are bred to serve the Changelings. Odo tries to show the boy, physically now a teenager, options for his life besides violence, but the boy's only drive seems to be to fight. When it is discovered that Starfleet has sent a ship to take the Jem'Hadar by force, the teen pulls a phaser and refuses to go along. Odo insists on returning the boy to the Gamma Quadrant and Sisko reluctantly agrees.
In a side plot, Commander Sisko's son Jake (Cirroc Lofton) is dating an older woman named Mardah (Jill Sayre), who is a Dabo girl at Quark's bar. Commander Sisko is very concerned and invites Mardah to dinner. Though originally intending to intervene and end the relationship, the Commander discovers through Mardah a hidden side to his son he realizes must be allowed to flourish.
Credits
Adapted from Wikipedia contributors, The Abandoned (Star Trek: Deep Space Nine). Paragraphs and formatting adjusted; illustrations, reference markers, block quotations and non-story material omitted.