The USS Enterprise-D is traveling through the Zed Lapis sector where it will rendezvous with shuttlecraft 13, carrying Counselor Deanna Troi, who is returning from a conference, along with the shuttle pilot, Lieutenant Ben Prieto. As the engineering crew is conducting maintenance of the ship’s dilithium crystals, the ship is flying at impulse, with the main engines deactivated. On the bridge, Lieutenant Worf tells Lieutenant Natasha Yar that deep space probes have picked up no vessels within three light years. Worf then shifts the conversation towards the martial arts competition on the Enterprise-D in three days.
He asks Yar if she is ready. She replies that she needs some practice with the Mishiama wristlock and break, and if she can use it on Worf, she can use it on anybody, an assumption Worf assures her is valid. He then asks who she is facing, and Yar says her first opponent is science officer Swenson. Worf says that she will easily defeat him. However Yar is more concerned about being beaten by Lt. Minnerly, a skilled kickboxer. Worf then boosts her confidence by telling her that she is favored in the ship’s pool to win. Yar asks Worf if he placed a bet on her. Worf replies that it is a sure thing. Yar then looks at Worf with a smile. Worf, embarrassed, moves away.
Helmsman Lieutenant Geordi La Forge reports to Captain Picard that the Enterprise-D will meet up with the shuttle in just over an hour. Picard comments how it will be good to have Troi back aboard, a sentiment Commander Riker agrees with. Suddenly, Worf receives an emergency distress call from the shuttle. The shuttle’s computer is severely damaged and impulse engines are off-line. Prieto can’t even tell where they are. Picard calls down to main engineering and asks chief engineer Lieutenant Commander Leland T. Lynch how long it would take to restore warp drive.
When Lynch complains that he’s in the middle of re-aligning the dilithium crystals, Picard tells him there is an emergency and they need warp drive. Lynch initially says it’ll be more than twenty minutes, and Picard berates him, telling Lynch that they don’t have that much time. Lynch promises to re-align the crystals by hand to get warp drive restarted immediately. La Forge then tells Prieto that he’s coming dangerously close to a planet, which Prieto confirms. Lieutenant Commander Data reports that the shuttle is near Vagra II, an uninhabited planet. Picard calls down to engineering again and Lynch tells him that although he offers no guarantees, he’s working on it and it’ll be about three minutes. Just then, Prieto reports that the shuttle is now out of control and has been caught in Vagra II’s gravity.
In engineering, the engineers are frantically trying to restore the Enterprise-D’s warp drive. Lynch, along with his engineering crew, quickly re-align the dilithium crystals into the warp reactor and Lynch decides to ignore the final safety check, telling the computer to restart the warp drive. When the ship’s computer begins the checklist, Lynch overrides the checks and they go directly to startup. As the warp reactor comes back online, Lynch calls Picard and tells him that they now have minimum warp drive. When La Forge reports course for Vagra II is laid in, Picard orders warp eight. Over the intercom, Lynch tells Picard he recommended minimum warp drive. Picard then tells Lynch he heard his command and to make it so.
Shortly thereafter, the Enterprise-D arrives at Vagra II although the ship is not reading the emergency signal from the shuttle. Data runs a scan of the planet.
There is no vegetation and no lifeforms on the planet, but the atmosphere is breathable for Humans. Worf locates the shuttle on the planet. It appears to be buried under debris. Picard asks if they can beam up Troi and Prieto; however, the debris appears to be blocking the ship’s sensors. Picard, seeing this as strange, orders Riker to prepare an away team. He chooses Data and Yar. Picard signals Doctor Beverly Crusher to join them.
On Vagra II, the shuttle’s nacelle has been ripped off and the shuttle itself has been embedded within a rock face. The away team materializes on the barren surface of the planet. Dr. Crusher notes that the signals inside the shuttle are weak. The away team begins to walk over to the shuttle, but a giant black liquid pool is blocking the way. Lt Yar suggests that they walk around it, just to be on the safe side. However, the black substance follows the away team to the right side. Yar then suggests that they go to the left, but the substance still follows them. Riker reports the problem back to Enterprise, even though he’s unable to articulate exactly what the problem is.
Crusher prepares to step over a narrow part of the pool, but Riker stops her. He then asks if the creature has a skeletal structure. Data scans with his tricorder, however, he cannot confirm Riker’s question. Picard asks Data if the black substance is a lifeform. Again, Data cannot confirm. When asked finally if it is possible that this pool is alive, Data says it is but again, he has insufficient information. Then they hear an ominous voice calling Data “Tin Man” and a figure begins to slowly arise from the black liquid. Picard asks Riker what he sees, and Riker simply replies, “Trouble.“
Picard signals Riker and comes to the conclusion that the placement of the creature and the shuttle’s crash landing cannot be a coincidence. Picard asks Riker to try to communicate with the creature. Riker greets the creature. The creature states that his name is Armus. He asks why the crew is there. Riker explains that they mean no harm and they have injured crewmembers on the shuttle. He asks permission to pass over. Armus states that he still has not given him a good enough reason. Riker states that preserving life is important to all Humans. Armus suggests the Enterprise-D crew leave the planet. Yar walks up to Armus and says that they will not leave without their crew and that they will not harm him.
Yar begins to walk over to the shuttle and is hit by a blast of energy from Armus and knocked away. Riker and Data react quickly and fire their phasers at Armus. Dr. Crusher rushes over to Yar, followed by Riker and Data. Picard asks for a report on the situation. Data says they fired on Armus, but their phasers had no effect on him. He seemed to feed off their energy. Armus retreats back into the black liquid. Picard inquires about Yar’s condition. After scanning her body, Dr. Crusher grimly reports that Yar is dead. Picard tells the transporter chief to beam up the away team quickly. The away team rematerializes on the transporter pad.
In sickbay, Dr. Crusher and her medical assistants are desperately trying to revive Yar. Picard asks for a report on Yar’s condition. Crusher reports that it is unchanged.
Riker and Data stand in the back, joined by Picard, waiting and watching. Dr. Crusher puts Yar on total life support, but Yar is still not responding and her synaptic network is breaking down. Dr. Crusher, seeing no other choice, decides to go for direct reticular stimulation. The energy goes into Yar’s body, but she is still flatlining. Dr. Crusher then pronounces Yar officially dead, and that Armus sucked the life right out of her.
On Vagra II, Armus moves toward the shuttle. Inside, Lieutenant Prieto is unconscious, lying down on his console. Troi is uninjured. She taps her combadge and tries to contact the ship. Armus is blocking the communication. She can feel Armus’ presence. Armus taunts her by saying that her friends deserted her and even killed one of them. Troi says she knows, she felt her die. Armus then says that he wanted to kill Yar to amuse himself. Troi tells him that he thought it would amuse him, but it did not. Troi senses he has a great need for something. Troi asks Armus to let her and Prieto go, and that the crew of the Enterprise-D will not give him what he wants, to break their spirit. Armus replies that if breaking their spirit amuses him, he will do it.
In the conference room on the Enterprise-D, the senior officers are arguing and talking over each other about Yar’s death and how she did nothing to provoke Armus. Only Worf and Picard remain silent. Picard taps the table with his finger. Picard tells the crew that Yar’s death is painful for all of them, but they will have to put it aside until the crisis is resolved. Picard makes Worf an acting chief of security. Worf accepts. Picard asks about the condition of the shuttle crew. Crusher says the life signs are faint, but the sensor readings are fluctuating, which means they may not be accurate. Riker suggests to Picard that the attack on Yar may not have been random, and asks to go down to the planet again. La Forge volunteers to join the away team; his VISOR may see something in Armus that the other crewmembers may not see. Picard agrees. Riker asks Worf to join them, but Worf believes he will be better used at tactical.
The away team sees Armus stretched out on the shuttle. Armus is surprised that the away team came back for Troi and Prieto. Troi senses something in Armus, that he was abandoned by his kind. Troi says he cannot hide the emptiness he feels from her. Armus goes back to his liquid state.
Back on the Enterprise-D, Worf and acting ensign Wesley Crusher are monitoring Armus from a science station. Worf notes that Armus’ energy went down when he enveloped the shuttlecraft. Picard asks them to chart it and to see if there is a pattern.
On the planet, Armus returns to his humanoid state and speaks with Riker. La Forge examines Armus with his VISOR discreetly as Riker pleads with Armus to see their injured crewmembers, with Dr. Crusher making an impassioned plea to Armus. Armus says she can, but only if she says please. Crusher submits to Armus’ strange request and starts towards the shuttle. Armus then changes his mind and will only allow Crusher to talk to her. After a moment of hesitation when Crusher wonders how that will work, she taps her combadge and calls for Troi. Troi responds and says she is fine. Armus is angered when the crew continues to ask him about going over and helping their crewmembers, which he views as ungrateful. He then rises up again, but taller than before. Armus uses his powers to throw Data’s phaser and La Forge’s VISOR away. La Forge, blinded, falls to his knees looking for his VISOR. Data directs him towards the VISOR, but Armus moves it away. Data then refuses when Armus demands that he try to help La Forge again, knowing he will just keep moving the VISOR away anyway. Angry that the crew won’t amuse him, Armus allows Data to retrieve the VISOR then leaves.
Armus re-envelops the shuttle, and on further probing from Troi, reveals how he came to be. The original inhabitants of Vagra II devised a process via which all their negative drives would be physically manifested as a “dank and vile” second skin, which could then be shed. This left them as “creatures whose beauty now dazzles all who see them,” who then left the planet, while the parts that they left behind coalesced into the singular being that is Armus. Troi expresses sympathy for him, but this causes Armus to temporarily lose cohesion. He becomes enraged again, he shakes the shuttle, then moves over to the away team. Suddenly, Riker falls to the ground and is dragged toward Armus’ liquid state. Riker screams for Data’s help, but Armus threatens to kill Riker if any of them touches him. The first officer is sucked into the slick and disappears beneath the surface. Picard orders the away team to return to the ship, but Armus warns that if they leave, Riker and the crash survivors will be killed. Data, Geordi and Beverly gasp as Riker’s lifeless face briefly surfaces, wracked with pain, before disappearing back into the pool.
Picard, after seeing the grave danger his crewmembers are in, decides to beam down. Troi, feeling her imzadi, Riker, in pain, pleads with Armus to let him go. Armus continues taunting Troi, with her begging him to let the away team go. He considers it, but then realizes that Picard has beamed down. Picard asks if Riker is still alive. Data surmises that, since death can no longer alleviate Armus’ boredom, then Riker is, indeed, still alive. Picard asks to see his crewmembers, and Armus asks Picard to entertain him, but Picard refuses. Armus replies that he will have to provide entertainment for himself.
Data, under Armus’ influence, takes out his phaser and points it at Crusher and then Picard. Armus asks Data how he would feel if he was responsible for the death of Captain Picard. Data notes that he is not in control of himself, thus he would not be an instrument of his death. Armus then makes Data point the phaser at Dr. Crusher, then La Forge, then finally, has Data point the phaser at his own head. Armus finally has Data drop the phaser from his hand. Data feels that Armus must be destroyed, since he is capable of cruelty and sadism and he cannot be redeemed. Picard then asks Armus if he can see Troi and Prieto. Armus lets Picard see one member of his crew, Commander Riker, covered in black, who is finally brought up to the surface by Armus.
Picard tells Armus that this is now between him and Armus. He tells Armus to let the Enterprise-D beam up the remaining members of the away team. They are beamed back to the ship; Picard is finally allowed to see Troi and is taken there by Armus. Picard, in the shuttle, checks Prieto’s pulse and finds that he’s still alive, while Troi asks if they were able to revive Yar. Picard, regretfully, tells her that they weren’t. Troi is saddened by the loss of her friend, but Picard is able to find out about Armus’ past, and works out how to distract him long enough for Troi and Prieto to be rescued.
Armus brings Picard back outside the shuttle, and asks to be taken aboard the Enterprise. He makes it clear that he wants to find Vagra II’s original inhabitants and avenge himself upon them. Picard attempts to sympathize with Armus, who irately dismisses his attempts and taunts him over Yar’s death. On the Enterprise, Worf and Wesley notice that Armus’ energy field has almost weakened enough for Troi and Prieto to be transported, and set the computer to automatically beam them out when the field weakens sufficiently.
In response to Armus’ claims to be the embodiment of evil, Picard says that true evil would be allowing Armus to force them into giving him what he wants. Armus threatens to kill Picard and the shuttle crewmembers, to which Picard points out that if Armus murders them, he will still be immortal and alone, forever, on Vagra II. Armus lets out an angry scream, and is distracted enough and the Enterprise-D beams out Troi and Prieto from the shuttle. Finally, Picard announces he will not take him anywhere, at which Armus yells out an enraged scream as the Enterprise-D beams up Picard, once again leaving Armus as the only lifeform on the entire planet.
Back on the Enterprise-D, Picard orders that the shuttle be destroyed with a photon torpedo fired from the ship so that Armus will not have a chance to leave Vagra II and declares the planet off-limits. Still, as Picard notes in his log, the damage has already been done.
On the holodeck, a funeral on a grassy knoll with a bright blue sky for Yar has begun. All of the senior staff – Worf, Data, La Forge, Beverly and Wesley Crusher, Riker, Troi, and Picard – attend the service. To begin the service, a hologram of Yar is played, with her noting all of the exceptional qualities that each member of the crew possess and what she learned from them. The service concludes when the hologram of Yar fades away. Everyone leaves the holodeck, except Data and Picard. Data notes that, during the service, he was not thinking about Yar, but how empty it will be without her. He asks if he missed the point of the service, but Picard assures him that he understood it completely.