Crusher plays host to a motley crew of alien scientists she has assembled in the hopes of validating the theoretical work of Ferengi Dr. Reyga (Peter Slutsker), who has developed an unproven new shield technology that can supposedly withstand the heat of a star's corona. His work is not taken seriously, however, because Ferengi are apparently so lowly regarded in scientific circles that most don't even grant that "Ferengi" and "scientist" can be said in the same sentence. That reveals a thinking that would seem awfully implausible (how could the Ferengi have ever developed space flight without scientific minds?) if not for the fact the Ferengi have been portrayed as so relentlessly one-note stupid throughout TNG's run as to have made me think on multiple occasions, well, "How did the Ferengi ever develop space flight, anyway?"
The testing of this shield technology requires a lot of danger, because for some reason the technology cannot be tested on an unmanned shuttle piloted by remote. Because for no other reason than the plot requires it, the shuttle must be piloted by a living person, which seems not simply contrived and implausible, but foolish: If you didn't believe this technology was sound, would you pilot a shuttle into the corona of a star? Just asking.
The volunteer test pilot, the Tarkarian scientist Jo'Bril, ventures into the inferno of the corona, has a sudden gasping fit, pilots the shuttle out, is beamed to sickbay, and dies on the operating table. What went wrong? Did the shield fail? If not, why wasn't the shuttle incinerated? Crusher is suspicious, then things turn even more curious when Reyga turns up dead with clues that indicate possible suicide but point with bright neon arrows to more-possible murrrrrrr-derrrrrrrr. Did one of the other scientists engineer an elaborate plot to sabotage the flight and then kill and discredit Reyga, and perhaps steal his scientific breakthrough for themselves?
"Suspicions" is a who-cares murder mystery told in hackneyed narrated flashback (as if this were some sort of film noir) as Crusher relays to Guinan the details of this somber mess that ultimately will supposedly cost Crusher her career, but actually not. Reyga's death is unsolved, yet no one on the Enterprise seems to care except Crusher, who as the story's lone-wolf heroine must press on even with the world aligned against her. Much is made of the fact that Crusher orders an autopsy of Reyga against the wishes of his family (leading to aforementioned supposed end of Crusher's career, etc.), and yet at the end, having violated the rules apparently means nothing so long as she ultimately proves there was actually a killer in the midst. (One actually has nothing to do with the other and she should still face the ethics panel, but, seriously, why pretend any of this has consequences?)
The characters are paper-thin vessels (the other scientists are a Klingon, a Vulcan, and a human, none of which deserves mention in this review, but I'll do it anyway) carrying only the plot pieces, which assemble into a story of relative nonsense and absolute inconsequence. The big twist is that Jo'Bril is the killer, having earlier faked his own death and who now appears in the show's finale — in which Crusher attempts to prove the initial flight was sabotaged by taking a second flight, using the logic that the shuttle won't burst into flames because this time it wasn't sabotaged, I guess.
Words escape me as to how many silly assumptions this line of thinking requires, but never mind, because Jo'Bril is aboard the shuttle and confronts Crusher and goes into full Talking Killer exposition mode by conveniently explaining to her in the most heavy-handed fashion imaginable every remaining plot question: the motivation behind his faked death, the — yes — murder of the Ferengi, how he intends to now steal the technology for himself (and turn it into a weapon, bwahahaha!), and, for all I know, even why the dog did it in "Aquiel" — which is the only episode of season six more mind-numbing than this one.