Plot summary
The episode begins with Bok (a former Ferengi DaiMon whose son was killed in a battle with the USS Stargazer, then commanded by Picard) announcing his intention to kill Picard 's son in revenge.
Picard, who is not aware of having a son, eventually locates Jason Vigo, the son of a woman named Miranda Vigo, with whom Picard had had a past relationship. The results of a DNA test confirm that Jason is indeed Picard's son, but Picard's attempts to bond with Jason prove difficult, and he is dismayed to discover that Jason has a criminal record, having been convicted of petty theft and trespassing. Meanwhile, Bok beams to the Enterprise twice (using subspace transport technology) to repeat his threats, and Jason suffers attacks from an unknown disease.
Finally, Bok beams Jason off the Enterprise and onto his own ship. La Forge determines that the transport is occurring via a small transport platform, and that research into subspace transporter technology was abandoned by the Federation because of its extreme unreliability and high energy requirements.
Picard then beams to Bok's ship via the Ferengi's own subspace transporter, where he confronts Bok and three other Ferengi and reveals that Dr. Crusher has discovered that Jason Vigo is not, in fact, Picard's son. Bok had resequenced Jason's DNA so that Picard would know how it felt to lose a son, but Bok's technique was flawed, and the deception was exposed when Crusher determined that Jason's disease was normally inherited, yet neither his mother nor Picard had it.
Realizing that there was no profit to be earned from Bok's revenge scheme, the three other Ferengi then disarm Bok and release Jason. After gladly hearing the news that Jason's condition is responding well to Dr. Crusher's treatment, Picard invites him to stay on the Enterprise a few more days. However, Jason decides to return to his life on Camor V to "straighten things out." In the transporter room, after Jason suggests he look him up should he ever be in the area, Picard finally bonds with his 'son' by presenting him with a Gorlan prayer stick, a rare artifact that Picard had traded a valuable bottle of Saurian brandy to obtain. Jason is sincerely touched by Picard's generosity.
Credits
Adapted from Wikipedia contributors, Bloodlines (Star Trek: The Next Generation). Paragraphs and formatting adjusted; illustrations, reference markers, block quotations and non-story material omitted.