S1E13 · Datalore

While on the way to Starbase Armus IX for computer maintenance, the Enterprise arrives at the planet Omicron Theta, the site of a vanished colony where the starship Tripoli originally found the android Data (Brent Spiner). An away team travels to the surface and finds that what had been farmland is now barren with no trace of life in the soil. The team also finds a lab which they discover is where Dr. Noonien Soong, a formerly prominent but now discredited robotics designer, built Data. The team also find a disassembled android nearly identical to Data and return with it to the ship.

As the course to the Starbase is resumed, the crew reassemble and reactivate Data's "brother" (also played by Brent Spiner) in sickbay. He refers to himself as Lore, and explains that Data was built first and he himself is the more perfect model. He feigns naiveté to the crew, but shows signs of being more intelligent than he is letting on. Later, in private, he tells Data that they were actually created in the opposite order, as the colonists became envious of his own perfection. He also explains that a crystalline space entity capable of stripping away all life force from a world was responsible for the colony's demise.

Lore then incapacitates Data, revealing that he plans to offer the ship's crew to the entity. When a signal transmission is detected from Data's quarters, Wesley Crusher (Wil Wheaton) arrives to investigate. He finds Lore, now impersonating Data, who explains that he had to incapacitate his brother after being attacked. Wesley is doubtful, but pretends to accept the explanation. Soon after, the same crystalline entity that had attacked the colony approaches the ship. Lore, still pretending to be Data, enters the bridge as the object hovers before the Enterprise and explains that he incapacitated his brother by turning him off, causing Doctor Beverly Crusher (Gates McFadden) to be suspicious, since Data had previously treated the existence of such a feature as a closely guarded secret.

Lore then explains that he can communicate with the crystalline entity and suggests to Captain Jean-Luc Picard (Patrick Stewart) that he should show a demonstration of force by beaming an object toward the entity and then destroying it with the ship's phasers.

Lore's attempts to imitate Data are imperfect, though, arousing Picard's suspicion, especially when Lore does not recognize Picard's usual command to "make it so". Although Picard sends a security detachment to tail him, Lore overpowers Lt. Worf (Michael Dorn) and evades pursuit. Meanwhile, the suspicious Dr. Crusher and her son, Wesley, reactivate the unconscious Data, and the three of them race to the cargo hold to find Lore plotting with the entity to defeat the Enterprise. When Lore discovers them, he threatens Wesley with a phaser and orders Dr. Crusher to leave. Data quickly rushes Lore and a brawl ensues. Data manages to knock Lore onto the transporter platform, and Wesley activates it, beaming Lore into space. With its conspirator no longer aboard, the crystalline entity departs, and the Enterprise resumes its journey to the starbase.