The Enterprise unexpectedly passes through a wormhole, causing everyone in the crew, except for Data, to lose consciousness for 30 seconds. But as a number of strange inconsistencies are discovered, it appears that the crew has in fact lost an entire day, a day in which they were actually awake. Not only have they all lost their memories, but it becomes clear that Data is concealing the truth about what happened during the missing time.
Beginning in the third season, show runner Michael Piller instituted a very rare policy for television -- he directed the production to accept script submissions, unsolicited and unrepresented by agents, from the series' own fans. This was one occasion on which that policy bore fruit. "Clues" was an idea submitted by a hopeful fan of the show. Piller thought the idea was first rate, but found the writing itself (particularly the dialogue) to be in poor shape. He contracted an outside professional, Joe Menosky, to do a polish draft, which was very well received. Not only did the series get an episode out of it, it got a new staff writer; Menosky was offered a permanent position on the writing staff.
Mysteries on Star Trek are seldom that compelling. They almost always turn on some vital information an alien-of-the-week is withholding, and are invariably resolved with a swim through technobabble. Actually, this episode is awash with technobabble too, from Crusher's growing moss to out-of-sync transporter trace biorhythms to tampered computer clocks. But what makes the crucial difference here is that the person withholding information is one of our own.
It's truly fascinating to watch Data "lie" in this episode. Given his lack of experience, he's unsurprisingly quite bad at it. When pushed into a corner, he responds with some incredibly suspicious variation of "I cannot dispute that it appears I am not telling you the truth." And this only deepens the mystery for the crew and the audience, as we wonder what could have happened that was so terrible that Data of all people would conceal it.
The revelation is the truth is perhaps a bit of a letdown: the fact that the Enterprise encountered a race of xenophobic aliens called the Paxans. The idea is compelling, but perhaps for lack of time in the episode, the aliens themselves are remarkably... well, "convenient." They apparently have the power (and immediately, the desire) to simply destroy the ship and everyone on board. Yet twice, they are almost instantly agreeable to a "memory wipe" solution. I guess there's just a strange mix of mercy and ruthlessness here that doesn't quite track for me. The "what" behind the mystery is certainly compelling, but the fact that the Paxans are dealt with so easily undermines their credibility as a threat. The way Data is acting throughout the episode, I suppose I expect a bit more of a menace.
If a few extra minutes could have gotten the writers the time to give the Paxans sharper teeth, I know where I would have taken them. The episode opens with a long Dixon Hill sequence that doesn't serve much purpose in my mind. Sure, it's fun to see Dixon Hill again, and fun to see Whoopi Goldberg play some comedy by stepping into that world. But did the episode really need to present us a tonal echo for "mysteries are compelling," as opposed to just showing us a compelling mystery? Did we really need several minutes of watching Guinan try to talk her way through an imperious secretary? And if you're going to put Guinan in an episode, is it really going to be just for that and not to appear anywhere else in the story? Perhaps this extended, unnecessary sequence is a consequence of the episode's fan origins; it smells like fanboy wish fulfillment to have Guinan and Dixon Hill in your episode.
- There are a few firsts in this episode. We see Worf teaching a martial arts class for the first time. Nurse Ogawa also makes her first appearance... though strangely, she only gets a first name here, Alyssa, and not a last name.
- Some fans of Red Dwarf have suggested this episode was actually ripped off from an earlier episode of that show. "Thanks for the Memory" apparently had a similar plot.
- When playing Dixon Hill on this occasion, Picard intermittently adopts a bad Chicago mobster kind of accent that I don't recall him embracing in previous adventures.
- The series somewhat frequently seems to end a Data-centric episode with a tight closeup on his face. I suppose they do it because Brent Spiner is the master of giving a truly subtle expression that lets you in on Data's thinking without actually showing what we'd consider full "emotion." In this episode, it's a very slight smile of satisfaction that this time, the plan to cover up the Paxan encounter has worked.