Nutshell: The alien sci-fi setup is reasonable and much of the imagery is clever, but the ending is unfocused and doesn't really work.
When the Voyager tries to pass through space claimed by xenophobic aliens, the crew suddenly finds itself in over its head with visions and illusions—but no explanations.
There's a sci-fi freshness to this story that I've only felt one other time so far this season on Voyager—that being the standout episode "Projections." Narratively speaking, however, Jeri Taylor's teleplay is uneven—lacking focus and direction while jumping from character to character as it tries to resolve itself. Still, "Persistence of Vision" is a vast improvement over the last four Voyager offerings.
The episode initially starts as a stressful day of scheduling for Captain Janeway, leading the Doctor to order her to run her holodeck relaxation program. But when Janeway begins seeing holodeck objects (and then later holodeck characters) outside the holodeck, the episode seems to be turning into a "Janeway goes insane" show, something which is quite entertaining for the first three acts.
Unfortunately, when the plot begins to take form in the latter two acts, the story suddenly shifts directions and tries to tackle every character by giving him or her something interesting to do. Taylor's script seems all over the map. However, thanks to some interesting imagery and a cool-headed direction by James Conway, the plot holds together and the story continues along at a reasonable pace.
The plot: Somehow, in an attempt to take over the Voyager, a mysterious alien presence is manipulating the thoughts of the crew; distracting them with elements of their own past. This causes any crew member who is unable to resist this mind control to fall into a useless, catatonic state. Such distractions include Janeway seeing her fiance Mark, Tuvok talking to his wife, Paris being called a loser by his father, and Torres allowing herself a passionate affair with Chakotay. Before long, the entire ship falls under the spell, except for Kes and the Doctor. Meanwhile, three ships come out of nowhere and surround the Voyager.
This leaves it up to Kes to attempt to reverse the alien's mind control by executing a technical procedure Torres had set up in engineering. Here, the mysterious alien takes the form of Neelix and tries to take over Kes' mind as well. Kes is able to fend off the alien's mind attack by turning it against him with her own mental powers. This causes the mysterious alien to fall unconscious long enough for Kes to revive the crew.
Once revived, Janeway goes to engineering to negotiate with the alien. "Why did you do this to us?" she asks him. He replies flatly, "Because I can." At that, Janeway threatens to lock him in the brig to prevent him from preying on other travelers. Here, the episode throws a rather unexpected and interestingly unsettling twist: The alien replies, "But, you see, I'm not really here," and then vanishes into thin air. The three ships vanish, too.
Now this kind of alien threat is fresh. It's bizarre and different—characteristic of what we should be seeing in the Delta Quadrant. It's just too bad the alien's motives are so vague and underwritten. It's also too bad Taylor's script doesn't see Janeway through the end as the episode's storytelling conduit. It should have been Janeway saving the ship in the episode's finale, not Kes. While this had the potential of being a really good Janeway episode, Taylor instead decides to spread it around. The result is a story that gives everybody some good material, but doesn't have a strong sense of narrative.
Nevertheless, I'll gladly accept "Persistence of Vision." It has some good sci-fi elements, and considering the long drought Voyager has been experiencing, this light rain is the first step to alleviating it.