While passing Omicron Theta, the USS Enterprise-D stops to investigate the site of Data‘s discovery. However, Data is in his quarters practising sneezing. Wesley Crusher asks him if he has a cold. Data has never heard of such thing (at least not in reference to an illness) so Wesley has to explain. Data presses that Humans sneeze for other reasons and he’d like to learn how to do it so he will better “fit in” with the crew. Wesley wonders out loud how Data could be practicing sneezing in a time like this; as they are about to arrive at his home planet. Data clarifies that he is excited to see his point of origin, but that he is also interested in sneezing. On the bridge, Lieutenant Tasha Yar signals that the planet is class M but has no life, not even vegetation, which is strange as the crew that found data reported farmlands. Picard would have loved to lead the away team, Riker is opposed to that idea, given that the entire colony disappeared. Instead, the first officer leads the away away team that beams down to the spot where Data was found.
The away team arrives on a dead planet, and starts analysing the soil. Data recognizes the area, and points to where he was found, 20 meters away. It is a hollow with a rock wall. He was found in the open, and was apparently activated by a marker beacon that detected the crews’ presence. Geordi La Forge examines the rock wall with his VISOR and sees that it was man-made. That triggers a memory in Data’s brain, and he remembers that the collonists hoped to remain hidden, but their fear to being discovered lead them to store their memories in him.
Jordy finds a hidden door in the wall that opens onto a passage that leads to an underground shelter. No life signs register on Tasha’s tricorder, even inside the complex. The away team goes down one of the corridors before coming to a door that leads to a laboratory, where Data recalls impressions of his basic functions being tested. There are children’s drawings on the wall, all apparently of the same scene. Data doesn’t know what they represent, only a sense that they refer to something dangerous.
Riker presses him and asks if he can remember anything else about the lab. Data replies that he can remember one of the machines being used by a Dr. Noonian Soong. La Forge recognizes the name of Earth‘s foremost robotics scientist. He tried to create a positronic brain, but failed and then disappeared. Now, they realize he went to Omicron Theta under a different name to continue his work.
Data, La Forge, and Riker continue to search the lab, while Natasha Yar and Worf search the rest of the bunker. They find molds for making Data’s skin, and Yar reports that the rest of the bunker is empty. Then La Forge comes across a storage area. Inside, they find another android identical to Data. Data is excited by the discovery, and wonders if that could be another android like him, or even his brother. Riker agrees to bring the other android back to the Enterprise, and try to assemble it.
Back on the Enterprise, a team of engineers and technicians try to reassemble the android. Chief Engineer Argyle confirms that “it” has the same body parts as Data. He then very hesitantly ask if he can examine Data if he needs more information, comparing the internal circuitry, and Data agrees with a nod of the head.
Data then joins Captain Picard, Commander Riker, and Geordi La Forge in the observation lounge to discuss the situation. Everyone seems to be tip-toeing around the subject, so Picard reminds everybody that if it feels awkward to be reminded that Data is a machine, then just remember that humans are just another kind of machine. He then states that they should handle this situation like they would anything else and continue the briefing.
Data wonders why he was given a human form, and Jordy says that it must be to help Data interact with humans more easily. Riker shows the captains the drawings they took from the lab, suggesting they might be linked to the colony’s disappearance.
Dr Crusher calls, and Data returns to the lab where the other android is being assembled. He shows Crusher his off switch, asking her to keep it secret. Then she and Argyle open him up and check his internal construction, so they could replicate that on the other android. After they close him up, Picard and Riker arrive in sickbay. The other android has been fully assembled, but he is still not active. Picard wonders aloud which was made first. Suddenly, the second android comes alive and says that Data was. He calls himself Lore, and says he was made to replace the “imperfect” Data.
Data and Picard talk in the ready room. The captain is troubled by the fact that Lore described Data as “imperfect”, but Data simply dismisses that as meaning Lore possesses certain abilities Data doesn’t. However Data believes that both he and Lore have very similar physical and mental capabilities. He also notes that Picard refers to Lore as “it”, meaning he, too, belong to the category of things. Picard then asks Data where his loyalties lie, and Data assures him that his loyalty is to Picard and Starfleet, completely.
Both Data and Picard go out onto the bridge where Wesley Crusher and La Forge are explaining the helm controls to Lore. Riker then says the first part of Pythagorean theorem, and Lore unthinkingly completes it, except the last words, which he claims he never really understood in the first place. Data tells him that he will learn more about those things once he his approved for being on the bridge. Lore is worried that he had committed an offence, but Wesley reassures him and tells him there are a lot of rules to learn. Data remarks that he judges Lore to be superior to him in regards to pleasing humans, to whcich Lore responds that was designed to be so human, and that he enjoys pleasing them.
Data leads him off to show him the rest of the ship, telling him Riker tricked him into revealing he knew more than he let on. He warns him not to underestimate Humans, but Lore is dismissive. He tells Data not to be jealous of his ability.
They go to Data’s quarters, where Data checks up information about Dr. Soong. Lore calls him “Often Wrong Soong” , a joke that Data doesn’t get. Dr. Soong ruined his reputation by making wild promises about the positronic brain, promises that later turned to be true, and make both of them possible.
Lore asks when he will have a Starfleet uniform. When Data explains it will take a very long time, Lore replies that the system in place is there to compensate limited humans abilities. He also says that Data is beginning to think like a human, even though both of them are nothing like humans. Lore tells Data that he could possess the knowledge of hundreds of millions of lifeform of every kind, but doesn’t want to say more for the moment.
Data asks Lore again which of them was built first, and Lore admits he, himself, was. But Dr Soong made him so perfect that the colonists became envious of him and persuaded Soong to build a less perfect android – Data. Lore was too Human, understanding language and humor. Lore points out that he can easily handle speech, use contractions and understand humour.
Lore than states that he can help Data become more Human and Data says that he is obligated to report all of this. Lore agrees, and asks if he can use the terminal to learn more about the ship and its customs. Data asks that Lore reports everything he knows about the time he spent with the colonists. Lore, with an almost evil grin on his face, promises a report of great detail and accuracy. Data leaves, and Lore starts to read all about the Enterprise on the terminal.
On the bridge, Picard and Riker analyze Lore’s report. The colonists were killed by a Crystalline Entity that feeds on lifeforms, and is capable of stripping all life from an entire world. The two androids survived because Lore had been disassembled and Data not activated yet when the entity attacked. Data was left outside to be found by the first Starfleet crew responding to the signal, as a proof that Dr Soong’s experiment did work.
Yar tells Picard that Lore has left Data’s quarters to go to deck four, and Picard tells Data to check up on him. Once his gone, Yar asks the captain how much he trusts Data now, to which Picard replies that he trusts him completely. In Data’s quarters, Lore mixes a pill into some Altairian Grand Premier champagne which he offers to Data when he enters, as his first lesson in becoming more human : observe their customs. Lore says it’s an ancient ritual humans practice when the observe events of importance. He raises his glass and toasts to their discovery of each other. Data drinks the champagne, and realizes immediately something is wrong. He collapses, and Lore reveals that he learned to communicate with the Crystalline Entity, which he led to the colonists before he was disassembled. He is planning on attracting it to the Enterprise and give it the lives of the crew.
On the bridge, a subspace communication is detected coming from Data’s quarters, and Picard sends Wes down to check it out, discreetly. Lore is communicating with the crystalline entity. He tells it to identify him as Data. Wes comes in and “Data” tells Wes that “Lore” attacked him and he had to switch him off. His face twitches and covers it up, saying he’s been practicing Lore’s facial twitch. Lore/Data says he’s coming up onto the bridge, and after Wes leaves he uses a small tool and fixes his own twitch and causes one in Data.
Dr. Crusher asks Wes on the bridge what happened and he tells her Data turned Lore off, which makes her suspicious since it was their secret. “Data” arrives on the bridge, and tells Dr Crushed he had a change of mind about the off switch. La Forge then detects an unknown object approaching at high speed, which they identify as the crystalline entity. Data/Lore is pleased to see it, and says out loud that he finds it beautiful, which makes Dr Crusher even more suspicious.
The entity is staying stationary next to the Enterprise, sending no signals. The crew has no idea what it is made of. Picard says they need to question Lore. Wesley loudly protests that he doesn’t trust Data/Lore. Picard and Riker are both annoyed at his display and decide that Riker would go with Wesley and “Data” to see “Lore”.
Im Data’s quarters, “Data” approaches “Lore” and causes him to shake by using Data’s activation switch to rapidly turn him on and off. He tells Riker and Wes to leave, saying he can’t control “Lore”. After they leave, he kicks Data in the head in anger, causing part of his “skin” to come loose and exposing the circuitry on his skull.
On the bridge, Riker tells Picard what happens, but Wes is still not convinced. The Crystalline Entity brushes against the shields. “Data” rushes in and says he wants to talk to it. He tells it the Humans here are powerful, capable of injuring or event destroying it. It backs off, and “Data” suggests beaming something like a tree out into space and destroying it in a show of force. Picard agrees.
“Data” leaves, but Wes continues to protest. Wesley tries again to convince Picard that “Data” is really Lore, but the captain refuses to listen and dismisses him, telling him to “shut up, Wesley.”
Picard orders Worf to monitor what “Data” does, since it is unusual. Beverly, just as hurt as her son, repeats in shock, “Shut up, Wesley?!” Picard dismisses her also and orders them both off the bridge. Wesley, angered, starts to complain, but Beverly fearfully adds, “Shut up, Wesley” herself in an attempt to protect her son from further ridicule by the rest of the crew.
Worf steps into the turbolift with Lore, who then assaults him and knocks him unconscious. Meanwhile, Wes has managed to convince Dr. Crusher to stop off at Data’s quarters. She sees Data hurt on the ground and switches him on. He tells her he is not badly hurt, and they go to cargo bay 3 to stop Lore.
They sneak into the cargo bay and hear Lore talking to the Crystalline Entity. Lore spots Data and Wesley and threatens to kill the boy. Beverly comes out from hiding and pulls a phaser on him, but she is too close and he grabs it from her. He then tells her to leave and asks Data to cooperate with him or he will kill Wesley.
Dr. Crusher hesitantly makes her exit, but not before Lore fires his phaser at her, igniting the sleeve of her blue lab coat. Taking his chance, Data knocks the phaser out of Lore’s hand and they start to brawl. Data throws him into cargo containers and then onto the transporter pad where the phaser landed. Lore fires just as Wes is able to energize the transporter, beaming him out into space.
Picard, Riker, Yar, and Crusher enter with phasers drawn to find that Lore is gone. With no way to reach the crew, the Crystalline Entity leaves; Picard orders Data to get rid of that damn twitch and to find a proper uniform as the Enterprise resumes course for a computer refit.