Original air date: October 14, 1991
Riker, Data, and Dr. Crusher are on Melona IV, where a new Federation colony is being built. Riker's mutual flirtation with colony engineer Carmen Davila is interrupted by the sudden arrival of the Crystalline Entity, a unique spacefaring creature known for its ability to utterly scour all life from a planet.
Recognizing the danger, Riker orders everyone into some nearby caves in the hope that they will protect them, though Carmen perishes trying to rescue an old man. The officers and the colonists wait out the Entity's attack, not knowing whether they are about to be atomized as well. By the time the survivors are rescued by an away team, the Entity has simply vanished. As Riker emerges from the cave, he sees that the lush, Earth-like planet of Melona IV has been turned into a barren wasteland.
The Federation's best expert on the Entity, Dr. Kila Marr, beams aboard eager for the chance to investigate an attack so soon after its occurrence. Her first question is how the survivors on Melona IV survived when all previous encounters with the Entity resulted in total loss of life. Data chimes in with his theories, but Marr pointedly ignores everything Data has to contribute. She specifically requests that he not participate on the grounds that he is related to Lore, who brought the Entity to the Omicron Theta colony, where the entire population, including her son Renny, was killed. However, Picard insists that Data be a part of the investigation.
While investigating the caves, Marr directly accuses Data of colluding with the Entity, just like Lore did. Data reassures her that he does not share his brother's misanthropic temperament, though it does little to placate her. Later, however, once one of Data's suggestions ends up revealing a method for tracking the Entity, her attitude starts to change.
As the Enterprise begins tracking the Entity, Marr recommends a way to destroy it once they find it. To her horror, Picard insists on attempting to establish peaceful communications first. The captain's peaceful outlook is sorely tested when the ship receives a cry for help from a transport vessel just before it too is consumed by the Entity. Even Riker candidly admits to Picard that he sides with those who favor destroying the Entity before it can kill any more people. Picard overrules them, staunchly believing the Entity should be afforded the chance to negotiate a peaceful coexistence with other sentient life.
At his orders, Marr starts working with Data on a way of communicating via graviton pulses. As Marr starts warming up to Data, she learns that his positronic brain has been modeled after the Omicron Theta colonists, Marr's son Renny included. He even has some of their memories. Marr starts peppering Data with questions about Renny's life, since she was absent for so much of it. Data tells her that he was very proud to have such a brilliant scientist for a mother and recites one of Renny's journal writings with his Voice Changeling abilities. Marr is overjoyed and starts treating Data like a living embodiment of her late son.
When the Enterprise finally catches up with the Crystalline Entity, Marr is surprised by the beauty of the creature she'd spent her life hunting. They begin sending it a series of graviton pulses designed to get its attention. The Entity responds with a signal of its own, creating a pattern that implies intelligence. Then, without warning, Marr starts sending a much more powerful signal, destroying the Entity before anyone can stop her.
Giddy with revenge, Marr proclaims that the Entity can no longer harm anyone else. The fuming Picard orders Data to escort her to her quarters, where she'll be confined until further notice. Seeing that Marr has become unhinged, Data volunteers to stay with her a while. She pleads with Data as if he were her son to absolve her of what she has done and assure her that he understands why she did it. Data has no choice but to state that, based on what he knows of her son, Renny would have been very sad to know that she threw her career away for revenge. Marr is stunned to regretful silence.
Tropes featured in this episode include:
- Alas, Poor Villain: Regardless of how villainous one considers the Crystalline Entity or Dr. Marr to be, both of their stories end tragically.
- Beauty Equals Goodness: Played with. Marr is struck by how beautiful the Entity is, suggesting that she may have opened up to the possibility that it isn't evil incarnate. But we never find out, because she kills it anyway.
- Brutal Honesty: Data doesn't mince words when he tells the unhinged and mentally fragile Marr that her late son would be saddened by her recent actions.
- Call-Back: The episode is based around the events of "Datalore."
- Clear My Name: Dr. Marr briefly suspects that the colonists who escaped to the caves were spared due to Data's presence, believing that he—like Lore before him—was colluding with it. He, on the other hand, surmises that it was due to the combination of certain two minerals in the caves. Technically, he doesn't exactly prove his theory, but Marr realizes she was wrong about him on her own.
- Death Glare: After watching his hopes for communication go up in smoke, Picard turns to Dr. Marr, and he is, of course, righteously pissed off.
- Downer Ending: The Crystalline Entity is destroyed by Marr before diplomacy has a chance to prevail. To rub salt in the wound, Data tells her in all earnestness that her late son would likely have been very upset by her actions, as her career is effectively ruined.
- Double Entendre: Carmen flirts with Riker by inviting him over for dinner and promising him a particularly special "dessert." Riker all but devours her with his eyes.
- Fantastic Racism: Subverted. Unlike some characters, who distrust Data because he is an android, it becomes clear that Marr distrusts him solely because of her hatred for his brother Lore and her grief over her son's death.
- Fleeing for the Fallout Shelter: Typically the Crystalline Entity destroys all life on the planets it attacks; in this episode, however, Riker succeeds in evacuating all but two of the planet's population into a cave, saving them.
- Freudian Excuse: Marr has quite a large one with the death of her adolescent son, caused by the Crystalline Entity.
- He Didn't Make It: Riker regarding Carmen.
- Heroic BSoD: Riker's Girl of the Week is killed by the Crystalline Entity while trying to save an old man. Riker takes it pretty hard, which initially leaves him more open to Marr's position.
- Hope Spot: Marr is struck by the beauty of the Crystalline Entity, making it seem like she's reconsidered her stance on killing it. And it looks as though the Enterprise is succeeding in communicating with the Entity… just before Marr destroys it.
- It Can Think: The big question at the center of the episode is about whether the Crystalline Entity can think and whether it is aware that it is devouring sentient species. This should have been a bit clearer due to the fact that Lore already figured out a way to communicate with it and broker an alliance with it to eat the Omicron Theta colonists.
- Moby Schtick: Dr. Marr's obsession with the Crystalline Entity. To drive the metaphor home, Picard compares the Entity directly to a sperm whale killing cuttlefish by the millions in Earth's oceans.Picard: It is not evil. It is feeding.
- Non-Malicious Monster: How this trope applies to the Entity is a subject of debate. Though it clearly has some degree of intelligence, whether it is self-aware enough to understand the morality of its actions is never made clear. Picard prefers to assume that it is merely feeding, as any living being must to survive, and allow it the opportunity to go vegetarian before resorting to violence. How this would have turned out will likely remain a mystery forever.
- O.O.C. Is Serious Business: Riker has a rare moment of hostility toward Picard after Riker sides against him on the subject of killing the Entity. Picard suggests that Riker's personal feelings are getting in the way of his judgment, provoking an extremely frosty response from Riker.
- Planet Eater: The Entity devours every single life form on entire planets, right down to the bacteria in the soil.
- "The Reason You Suck" Speech: Data basically delivers one at the end of the episode, as he tells Doctor Marr that Renny would not have wanted her to kill the Crystalline Entity in his name, and would actually be very sad at what his mother has done to her career to get her revenge.
- Replacement Goldfish: Towards the end, Marr starts to see her late son Renny in Data. She even calls him by her son's name once.
- Revenge Before Reason: Marr's grief over the death of her son—and her desire to avenge him—is the sole driving force behind her actions.
- Riddle for the Ages
- We never find out why the Crystalline Entity spared the survivors in the cave.
- We never find out whether the Crystalline Entity was malicious or if indeed, as Picard suggests is possible, it's just innocently feeding.
- Sacrificial Lamb: Carmen, who dies to give the Entity's attack a more personal impact.
- Sanity Slippage: It becomes more and more apparent as the episode progresses that Dr. Marr's state of mind is not just unhealthy, but borderline unstable.
- Voice Changeling: At Doctor Marr's request, Data recites one of Rennie's recorded letters home, naturally doing so in Rennie's voice.
- Wide-Eyed Idealist: Picard is all alone in his insistence that the Crystalline Entity be given the opportunity to not be an all-consuming, planet-killing death machine.
- You Killed My Father: Dr. Marr is obsessed with hunting down and destroying the Crystalline Entity to get revenge for it eating her son Rennie.
