- Jonathan Frakes - William Riker
- LeVar Burton - Geordi LaForge
- Gates McFadden - Beverly
- Marina Sirtis - Deanna Troi
- F. Murray Abraham - Ru'afo
- Donna Murphy - Anij
- Anthony Zerbe - Dougherty
Lieutenant Commander Data (Brent Spiner) is temporarily transferred to an undercover mission observing the peaceful Ba'ku people. While on their planet, he malfunctions and reveals the presence of the joint Federation–Son'a task force observing the Ba'ku. Admiral Matthew Dougherty contacts the USS Enterprise-E to obtain Data's schematics but adamantly states the presence of the Enterprise is not needed. Captain Picard decides to ignore these orders and takes the Enterprise to capture Data. After stopping Data, Captain Jean-Luc Picard becomes suspicious of Dougherty's insistence that the Enterprise is no longer needed. His crew investigates the cause of Data's malfunction. They discover that the Ba'ku are technologically advanced, but have rejected its use to live simpler lives. Due to unique radiation or "metaphasic particles" emanating from their planet's rings, they are effectively immortal. Dougherty's allies, the Son'a, are a decrepit race who use medical techniques to prevent death; their excessive use of cosmetic surgery gives them a mummified appearance. The Enterprise crew also begin to experience the rejuvenation effects of the planet: Lt. Cmdr Geordi La Forge finds his eyes have regenerated and he no longer requires ocular implants; Commander William Riker and Counselor Deanna Troi rekindle their long-abandoned relationship; and Picard develops a romantic relationship with the Ba'ku woman Anij.
Data and Picard discover a submerged and cloaked Federation ship containing a gigantic holodeck set up to recreate the Ba'ku village. Data's malfunction stems from a Son'a attack, received when he discovered the vessel. Picard confronts Dougherty and learns that top Federation officers and the Son'a secretly planned to deceptively move the Ba'ku to the ship and forcibly relocate them to another planet to collect the source of the planet's radiation which will destroy the planet. Dougherty orders Enterprise to leave. Picard states the rejuvenation benefits of the radiation does not justify Dougherty's plans for the Ba'ku and violates the prime directive. He plans to alert the Federation of the forced relocation.
Picard is joined by some of his crew to help the Ba'ku escape from being abducted while Riker takes the Enterprise to a transmission range and communicate the violation to Star Fleet. The Son'a send robotic probes to locate and capture the fleeing Ba'ku. Their leader, Ahdar Ru'afo, convinces Dougherty to allow two Son'a ships to attack the Enterprise. Riker defeats the attacking ships and the Enterprise escapes. Their plan exposed, Ru'afo insists upon harvesting the radiation source immediately. Picard, Anij, and several Ba'ku are transported as prisoners onto the Son'a ship. Picard reveals to Dougherty that the Son'a and the Ba'ku are the same race and involving the Federation in a 'blood feud'. The Son'a are a splinter faction of Ba'ku who gave up their bucolic existence a century earlier to embrace the use of technology. They attempted to seize power but failed, and the Ba'ku elders exiled them from the planet, denying them the rejuvenating effects of the rings. The Son'a developed an artificial and imperfect means to extend their lives at the cost of disfigurement. Ru'afo kills Admiral Dougherty when he backs out of the plan and Ru'afo proceeds with his plan.
While Picard is escorted to be executed, he convinces the Son'a Gallatin to help him stop Ru'afo. Picard masterminds a ruse to transport Ru'afo and his bridge crew to the holoship and shutdown the harvester. Ru'afo discovers the deception and transports to the radiation harvester ship to manually restart the process. Picard follows, destroys the harvester which kills Ru'afo and is transported by the Enterprise. The remaining Son'a are forgiven and welcomed back by the Ba'ku. Picard arranges a meeting between Gallatin and his Ba'ku mother. The Enterprise crew take a moment to enjoy their rejuvenated selves before returning to their previous mission.
- "A British Tar" - Picard, Worf and Data