Enterprise discovers the missing starship USS Brattain and the crew begins to experience mysterious hallucinations.
This is mixed bag of an episode with good ideas but some uninspired execution.
The basic plot is good and contains a number of solid concepts. I like notion of the effects of REM sleep deprivation. I loved the hydrogen atom idea and how the mystery gets solved. As good a solution as it is, it feels like it takes an age to get there and when it we actually see it put into action it is fairly unsatisfying.
From a character perspective it is okay. Troi, Crusher and Data have strong moments of contribution, but others, although frozen out quite logically by the plot, do feel missed.
The visuals are the most inconsistent part of the episode. There are some scenes that are genuinely creepy like the Crusher morgue sequence and the way certain other scenes are filmed and edited, but then it's ruined by the obvious and repetitive bluescreen effect of Troi floating through space.
Performances are a mixed bag. Marina Sirtis and Gates McFadden are okay, but their scenes do not showcase their abilities particularly well. Brent Spiner is great as ever, but everyone else feels like they are going through the motions.