Revenant

Revenant is everything I could want from a Star Trek tie-in novel: the deep character studies, masterful management of tension, and social commentary that Star Trek does best, without any unnecessary or forced attempts to fix plot holes in canon, wish fulfillment, or appearances of legacy characters. It's epic, suspenseful, emotional, and it understands Star Trek. It's focused on the centuries-old joined Trill ops officer, Jadzia Dax, and even though this takes place right between two episodes of Deep Space Nine, it feels like it develops her character in ways that make the rest of the series better in retrospect.

An old friend of Dax asks her to talk to his daughter while she's on vacation to Trill, and doing so leads Dax to discover a massive criminal conspiracy going back a full century, and involving two of her previous hosts, Curzon and Joran. As Dax uncovers the plot, we see Kira acting as her best friend (something the show proper didn't have enough of), and Bashir and Worf acting as much-needed allies with a hint of romantic tension. We also learn a lot about Dax's history, including two full chapters on the life of the homicidal Joran. The villain, Vess, is of the mustache-twirling variety, grooming Trill into undergoing a surgery that kills them and leaves their body in control of the symbiont - a clone of Vess. Yet, such an evil exists only because of the failures of Trill society - motivated by and preying upon the Symbiosis Commission's lies, coverups, and mismanagement of the Trill initiate program, all of which were exposed in episodes of DS9 proper, in addition to its bureaucratic inefficiency.

You might expect this novel to amplify the trans interpretation of Dax, being a novel focused on the character and written by a nonbinary author, but the gendered aspect isn't focused on here. Rather, the story is about how Dax gains strength from having lived all of the lives she has, both as good, bad, and morally complex people. We learn what it really means to be a joined Trill, to be both Jadzia, Curzon, Joran, Torias... and Dax, in a way that also says something about how humans should look upon their own past. I think it's a beautiful interpretation of the character, that is both in line with the show and with its interpretations by many queer fans.