The USS Enterprise-D has begun orbiting the two major planets in the Beta Renner system, Antica and Selay. The two species of those worlds, the Anticans and the Selay, have both achieved space flight and have both applied to become members of the United Federation of Planets. However, the two species are mortal enemies. The Enterprise is to transport both peoples to a neutral planet called Parliament, in the hopes of resolving their conflicts. On the Enterprise, Captain Jean-Luc Picard, Commander William T. Riker and Lieutenant Natasha Yar stand in the transporter room wearing their dress uniforms awaiting the delegates.
The delegates from Selay beam on board. Picard introduces himself to Ssestar, a male Selay. Riker is about to lead them to their accommodations, but Ssestar insists that the Selay’s quarters be upwind from the Anticans and as far away as possible. Riker attends to this and leads them to their quarters. After the delegation leaves the transporter room, Yar tells Picard that neither species seems like promising Federation candidates. Picard agrees and believes that Parliament’s peacemakers may have difficulty satisfying the two species’ needs.
The Enterprise leaves orbit of Selay on course for Parliament. On the bridge, Lieutenant Commander Data notes that his sensors are picking up an unusual energy object ahead of the Enterprise. On the viewscreen, an enormous cloud is shown. Data notes that it is also traveling at warp speed. Picard, intrigued, orders Data to make a close sensor pass on the cloud, then jump back to warp speed so they are still on schedule for Parliament.
In sensor maintenance, Lieutenants Geordi La Forge and Worf are running diagnostics on sensor assemblies. La Forge wonders why Worf is so interested in routine maintenance on sensors. Worf tells him it is simply because captain Picard wants his junior officers to “learn, learn, learn”. Yar signals sensor maintenance to see if there are any problems with the systems, since they are making a close sensor pass. La Forge replies that all equipment is functioning perfectly, and the Enterprise begins scanning the cloud. Worf, while working at a console, hears a strange noise. He goes over to investigate, but his body is struck by swirling blue energy. Worf falls, unconscious. La Forge rushes over to his side and signals a medical emergency.
Dr. Beverly Crusher arrives in sensor maintenance with a medic. She is about to examine Worf, but he awakes, violently attacks the medic and throws him away. La Forge heaves himself on top of Worf, so Crusher can administer a sedative. Worf finally calms down and is taken to sickbay. Later, in Picard’s ready room, La Forge tells the captain that he could see a glow in sensor maintenance, and that Worf jerked as though something had hit him.
In the Antican’s quarters, Yar and Riker are attending to the Antican’s dietary requirements. Yar had misunderstood that the Anticans prefer their food live, not dead. Riker tells Badar N’D’D, the lead Antican delegate, that Humans no longer enslave animals for food purposes, rather they consume meat that has been inorganically produced from the ship’s replicators. Badar N’D’D finds this practice “barbaric”.
In sickbay, Crusher examines Worf. While she uses a medical tool, the energy thingy leaves Worf’s body and enters Crusher’s. Soon after, Counselor Deanna Troi enters sickbay to inquire about Worf’s condition, but Crusher is now acting strangely and Troi begins to notice. She asks if she is all right. Crusher responds, “Yes, perfectly. Both of us, quite normal now.” Worf awakens and inquires where he is. Troi responds that he is in sickbay and asks if he remembers what happened to him. Worf can only remember what happened prior to his accident and asks what he is doing in here. Troi replies that Crusher will tell him all about it, but the doctor promptly leaves sickbay without a word.
On the bridge, Picard and Data wish to examine the cloud further, since there are many unexplained mysteries surrounding it, but Picard tells Data that it will have to wait until the delegates are delivered to Parliament, and orders helmsman La Forge to take the ship to warp eight. Crusher enters her quarters, where she finds her son, Wesley Crusher, working at a desktop monitor. Wesley tells his mum that he is working on a project for his physical sciences class, where he is studying Dr. Channing‘s theory on dilithium crystals. Dr Crusher asks Wesley to tell her about it, which strikes Wesley as odd, since his mother has never shown interest in warp theory before. Wesley explains that Channing believes that it may be possible to force dilithium into more useful crystals. Dr Crusher asks if that would affect navigation. Wesley replies that this theory is related to engineering, not helm control. Crusher then remembers that helm is located on the bridge. Wesley then notices that his mother is now acting strange and wonders if she is all right, but she abruptly leaves without answering.
Dr Crusher arrives on the bridge and walks over to helm, manned by La Forge. She whispers that it must be the helm. La Forge replies that it is, unless there have been some changes that he is unaware of. Picard walks over to Crusher and asks about Worf’s condition. Crusher does not give Picard a lot of information and Picard presses her to give him an accurate diagnosis, since it involves a bridge officer. Crusher replies that she will have to run medical cross checks in the ship’s computer. She uses science station II next to Data. Data looks at her console and wonders what helm control has to do with medical cross references. Crusher remains silent. Then, the blue energy that was inside Crusher enters the computer. Crusher is disoriented and leaves the bridge.
Suddenly, Data cannot get any of the science stations to work. From engineering, assistant chief engineer Lieutenant Singh, reports that there is a failure with the warp drive circuits. Various other stations on the ship report failures, as well. Picard, seeing that the Enterprise is not even a year out of spacedock, asks Data what the chances are of the ship having all these failures. Data responds that it is a virtual impossibility.
In the conference lounge, Picard, Riker, Data, and Singh, along with other department heads discuss the various problems on board the Enterprise and solutions to them. Singh believes that an electronic short made its way into several systems, but Singh concedes that that should not be possible, as the affected systems do not interact with each other. Singh replies that chief engineer Argyle and all engineering staff are just as puzzled as they are. Picard wants an explanation for the system failures by the time the ship reaches Parliament.
In the Antican’s quarters, Riker and Yar confront and confiscate weapons from Anticans seen, near the Selay delegation’s quarters. Riker tells Badar N’D’D that all weapons, no matter what their basic function, will be taken away and that violence will not be tolerated on the Enterprise.
On the bridge, conn officer Worf announces that warp drive is failing yet again and the Enterprise drops out of warp. Picard asks Data to send a message to Parliament, informing them that they will be delayed. However, Data cannot send a message as communication systems are down.
In Picard’s ready room, Data states that if the Enterprise had all these system failures, the ship would have never left spacedock. Therefore, Riker and Data believe the Enterprise has a saboteur on board. Riker believes the Ferengi may have bribed the alien delegation to sabotage the Enterprise, as Ferengi have had contact with both the Selay and the Anticans. Picard asks if they have any more suspects, to which Riker tells Picard that he is beginning to sound like a “private eye”. Data wonders as to the meaning of the term “private eye”. Picard tells him that it is a person who solves crimes, like the immortal Sherlock Holmes, which piques Data’s interest.
In engineering, Wesley Crusher and Singh are trying to come up with solutions to the system failures. Wesley finds something interesting, but Singh reminds him that is scheduled for class. Wesley protests that he learns a lot more in engineering than in school, but the captain’s orders are very clear, and he reluctantly leaves.
In the Crusher’s quarters Wesley finds his mother, Beverly, sitting down reading a PADD. Wesley complains that he has learned more about starship operations than any of the senior staff care to admit, like Channing’s theory on dilithium crystals he told Beverly about earlier, to which she has no memory of. Wesley replied that he told her about it that morning, but she cannot remember.
Singh, in engineering, works at a console. He touches a button, and the same energy that enveloped Worf and Crusher strikes his body quite violently. It blasts Singh backwards and he falls unconscious, right next to the ship’s warp core. Worf, coming down a lift, sees Singh. He rushes over to him and checks his pulse. Worf inform Picard that Singh is dead.
Picard has begun an investigation into the death of Singh. In engineering, it is discovered that warp drive has been miraculously restored and the Enterprise can jump back into warp at any time. Wesley notices that the readings are different than when he left. Singh couldn’t have fixed the engines himself since the problem was inside of them. Worf signals the bridge, and the Enterprise goes to warp six, on course of Parliament.
In the Antican quarters, Yar again questions the delegates where they were during the time when Singh was killed. Badar N’D’D replies that they were eating for hours, because the animal they hunted was a large one. In sickbay, Crusher and Troi have called Worf to discuss his memory blockage, as well as Dr. Crusher’s. Troi announces that she would like to try hypnosis, as it may restore their memories as to what happened to them.
In the conference lounge, Data, adopting the mannerisms of Sherlock Holmes, discusses the possible involvement of the Selay and the Anticans in the ship’s systems failures and the death of Singh. Data, smoking a pipe, tells Riker and Yar that the two species were too involved in their own affairs to have disabled the ship and murdered Singh. The two species would rather kill each other than the crew. It’s elementary, my dear Riker. Sir.
Back in sickbay, Troi has begun hypnosis of Dr. Crusher, while Worf watches. Troi asks Crusher to remember what happened up to the point she had memory loss. She recalls walking up to scan Worf, but then, there was someone else, another presence in the room. Troi then snaps Crusher out of the hypnosis and replies that her responses were identical to Worf’s.
Troi reports her findings to Picard and believes that something invaded their bodies, as it is the only reasonable conclusion. Data replies that, since they have eliminated the delegates and the crew members as suspect, then whatever remains, however improbable, must be the truth. Therefore, Troi’s theory is possible.
On the bridge, Wesley Crusher is talking to La Forge. He tells him that the warp computer in engineering could not possibly have fixed itself. Suddenly, helm controls go down. La Forge tries to contact engineering, but communications are down too. The warp engines go down, too, and the Enterprise drops to impulse. Picard monitors the situation from the helm console when the blue energy emanates from the it and enters Picard’s body. La Forge asks the captain if he is alright, to which he replies, “everything is fine now”.
Picard, inhabited by the non-corporeal life form, wonders why the sudden drop to impulse. When La Forge responds that helm is malfunctioning, Picard replies that he should look again. And indeed, everything is back to normal. Picard orders La Forge to double back on their course and head back to the strange energy cloud. The entire senior staff is completely puzzled by this change of orders, since the ship is behind schedule for Parliament. Picard assures them that he wants to take another look at the cloud, since they only obtained minimal information on it. He also asks Councillor Troy if she believes a captain should explain every order, to which she responds in the negative.
In a corridor, Chief Miles O’Brien is following Badar N’D’D, who is demanding to see Picard to know why the Enterprise has changed course. O’Brien orders him to return to his quarters, but Ssestar comes out of his quarters and a confrontation ensues.
The senior officers gather together and discuss Picard’s strange orders. Troi senses that Picard is deliberately concealing something from her and that he may has become dangerous. If Picard is dangerous, they argue, he should be relieved of command, which Dr. Crusher could do, falling under her responsibilities as chief medical officer. Riker could also relieve the captain from his duties, but only if all commanding officers agree it is vital to do so.
Crusher and Riker arrive in Picard’s ready room to order a medical scan on Picard. He asks why, and Riker informs him that they believe he is under the influence of an alien life form. He refuses and believes they are hallucinating and working too much. He instead orders that all senior staff be examined. He then justifies turning the ship around by explaining that the search for knowledge is the primary mission, and asks if he need to call security to make them leave.
Later, Dr. Crusher comes with the test results. She hands it to Picard, who then casually tosses it aside. She walks to his side and asks if she is talking to the real Picard. The lifeform within Picard tells her that the Picard she knows is there, along with more, and that very soon, the both of them will be home.
The Enterprise arrives at the cloud, again. Picard walks out of his ready room and examines the cloud from the viewscreen. The lifeform tells the crew that when the Enterprise passed the cloud before it accidentally took a lifeform with it. The lifeform within Picard recalls the horror of being taken from the cloud, then going from body to body, trying to call for help, but in a way the crew couldn’t understand. Then, discovering the computer intelligence, it was able to slow the enterprise. It also stats that it regrets the accidental death of Singh. Troi asks Picard if he exists in combination with the entity in his body.
The entity reveals that both it and Picard have the same desires, for exploration and dreams beyond Human expectations. Since the lifeform is essentially an energy pattern, free of matter, Picard could literally go anywhere in his energy state. The lifeform plans to beam itself and Picard to the energy cloud, but not restore the matter pattern, and combine their energy signatures to become one. The crew pleads with Picard to reconsider, and Dr Crusher relieves the captain from his duties, judging him disabled and mentally incapacitated, but the lifeform fires the blue beams at the crew all over the bridge. Riker yells for security to restrain the Captain, but the entity is far too powerful. It leaves the bridge unopposed and travels to the transporter room, where the transporter chief incapacitated. The entity activates the transporter controls and beams away.
After searching for over an hour, the Enterprise still cannot find Picard’s energy pattern. Riker, seeing no other option, orders La Forge to set course for Parliament. But, Troi senses Picard. The combination was not possible in the cloud, and he does not belong with the rest of the lifeforms. Riker tells La Forge to move the Enterprise into the cloud, so they can find Picard’s energy signal. At first, there is no sign of Picard anywhere in the cloud, but on La Forge’s helm console, the circuits re-arrange to form a “P”. Data surmises that Picard has found his way into the ship’s systems. Data asks Troi and Riker to accompany him to the transporter room.
Since Picard’s physical pattern is stored in the transporter system, Data attempts to recombine his energy pattern, as he hopes that Picard has worked his way into the transporter. Data energizes and Picard materializes on the transporter pad. Picard has a vague memory of what happened to him, much like Worf and Crusher. Riker tells Picard that he should head down to sickbay, as Dr. Crusher believes Picard is very tired. Yar enters, with news that one of the Selay delegates is missing and the Anticans have asked the chef to broil reptile. Picard turns to Riker and tells him to take charge of the situation, as he believes he needs a rest. The Enterprise continues on course for Parliament.