The Enterprise is between assignments, allowing the crew some extra leisure time as they perform some routine exploration. Picard has invited Guinan to enjoy a Dixon Hill story with him on the holodeck, but just as the mystery is starting to unfold, Data calls in to report a scientific curiosity. Sensors have detected a T-Tauri type star within a stellar cloud that appears to have an Class-M planet in orbit, capable of supporting life.As they are approaching the system, they detect an energy distortion resembling an unstable wormhole — not unusual near a T-Tauri star. Before they have a chance to withdraw, they are pulled in, and Data turns around to find that everyone has been rendered unconscious.When they recover, Data reports that the wormhole stunned the crew for about half a minute. No major injuries or damage is reported. Thankful for their good fortune, they decide to play it safe and launch a probe to investigate the anomalous planet. Its telemetry shows it to be a mundane gas giant instead of the Class-M they expected, which Data speculates might have actually been from another system, detected through the unstable wormhole. Though puzzling, Picard decides it is not a mystery worth pursuing.However, yet another mystery emerges. Dr. Crusher comes to Picard with some alien moss samples that she had planted right before the incident. They have inexplicably grown a full day's worth, which neither of them can explain. When they ask Data for his opinion, he offers a Technobabble hypothesis based on a temporal theory with little relation to botany. It's clear that the senior staff is not buying it, and after Picard dismisses Data on an errand, La Forge admits his astonishment that Data would offer such a far-fetched explanation.With Data's state of mind in question, the crew investigates further without his knowledge. They uncover further evidence that significantly more than 30 seconds passed after the wormhole incident, and that Data falsified all of the computer's evidence to the contrary. Data admits to nothing when confronted, but also has nothing to offer in his defense. Apart from his reticence, Data has cooperated fully, which leads the crew to conclude that he is not acting maliciously, and may have been forced into silence for their own protection.This is not enough for Picard. Despite the risks, they return to the T-Tauri star system, where they find the original planet. Data implores Picard to leave, but to no avail. Troi enters the bridge, possessed by an alien, after which Data finally breaks his silence.The inhabitants of the planet are a race of extreme isolationists called the Paxans. The wormhole was actually a defense system designed to stun the crew of curious vessels so that they can be relocated farther away under the guise of being caught by a dangerous anomaly. But as Data was not affected by this technology, he was able to resist them, leading to a confrontation. The aliens don't want their existence made known, but destroying Enterprise might cause Starfleet to come looking.Using Troi to communicate by proxy, the Paxans agreed to a compromise: the ship would be allowed to leave as long as the crew's memory and computer logs were wiped and Data was sworn to secrecy. The crew tried to remove all evidence of the event, but the loose ends they overlooked were enough to unravel the conspiracy. Now that the ruse has failed, the Paxans again consider violence, but Picard convinces them to give the plan another try.
Picard: The plan failed because clues were left behind that suggested a mystery, and to many humans a mystery is irresistible [...] Consider the first time a run-through, a rehearsal to shake out the flaws. The second time will succeed if we leave no clues.
Paxan: You are a most unusual species. Worthy of a second chance. Proceed.Armed with the knowledge of what went wrong the first time, the crew's self-imposed cover-up succeeds on the second attempt. There are no lingering suspicions, and after noting the system as hazardous for the star charts, the Enterprise continues on its way.
- Aesop Amnesia: Picard's claim that Data would be "stripped down to the wires" as a consequence of his deception flies in the face of "The Measure of a Man", where Data was legally acknowledged to have the rights of an individual (a judgment that Picard himself argued in favor of). You might blame it on his obvious annoyance at Data's blatant evasiveness, but it's still a little jarring.
- Beware the Honest Ones: Data does his utmost to ensure the masquerade and try to throw the crew off the scent.
- Conflicting Loyalty: An odd case. Data has to obey orders from — in effect — two different Picards, one who ordered him to hide the truth for a good reason and one who's trying to find the truth without knowing better.
- Curiosity Is a Crapshoot: Picard refuses to accept Data's answers about what happened, and returns to the system where the crew was knocked out. This nearly gets them killed.
- Patrick Stewart Speech: Picard tries to convince the aliens that humans are naturally curious, and when inconsistencies (the moss, Worf's wrist, the ship's clock) made the cover story implausible, they were compelled to solve the mystery. The aliens accept this explanation.
- Spotting the Thread: The potted moss and Worf's broken wrist are the first clues to suggest the crew was out for far longer than Data claims.
- Talking Through Technique: One of the clues Dr Crusher discovers is that Worf's hand was broken and the bones set by a doctor. She realizes that she herself is the only person who would have set them that exact way.
- Techno Babble: Humorously lampshaded. Data gives a long-winded technobabble explanation for why the moss grew much larger than it would have and after he leaves, Picard asks Geordi if he believes him. Despite all their technobabble solutions, they do not.
- Tongue-Tied: Though they aren't willing to trust all 1000+ people on the Enterprise with their secret, the Paxans are willing to trust just Data. He certainly makes good on his promise; no amount of threats or cajoling gets him to open up.
- Violence Is the Only Option: At both encounters, the Paxans consider destroying the Enterprise to keep their existence a secret, though it's clear they'd prefer not to since they give Picard's alternative solution a try — twice, in fact.
- The Voice: The Paxans are never seen, only heard as a deep, unnatural voice when they speak through Troi (and even that is probably not what they really sound like).
- Wham Line:Picard: Who gave you the order [to lie]?
Data: You did, sir.
- The Worf Effect: Has greater plot relevance than usual in this episode. When it is discovered that Worf's wrist was broken during the crew's lost time, suspicion falls on Data due to his android strength, when in reality it was Troi while possessed by the aliens.