The Devil's Heart by Carmen Carter; Star Trek: The Next Generation hardcover novel, April 1993 (paperback February 1994).

The Enterprise is diverted to the site of a Vulcan archaeological survey, as the senior member of that team, T'Sara, is believed by her staff to be suffering from Bendii's syndrome, the Vulcan version of Alzheimer's disease. When the ship arrives, they find all the Vulcans dead, apparently at each other's hand. Further investigation show that the scene was staged, and the scientists actually murdered by other parties. Picard, who of course has followed T'Sara's career, seeks the item that would lead someone to cause such carnage, and then cover it up. He finds "The Devil's Heart," an artifact found in the history of many races, reputed to have tremendous powers to make its holder invincible.

Such an artifact naturally draws a lot of attention, and much of it goes through a nearby starbase, which is so out of the way it is lightly staffed with Federation personnel, but a crossroads of species from all over the galaxy. The bar owner there is a member of Guinan's race, who has turned her listening skills into a profitable trade in information. Guinan is not pleased with this turn of events.

While Orions and Ferengi seek the Enterprise for the gemstone, Picard begins to receive telepathic dreams of the history of the stone itself. The captain becomes convinced that the stone itself, apparently a fragment of the Guardian of Forever, a powerful time-travel device, has a destiny that must be fulfilled. And so, he sets out to fulfill it, all the while becoming more attached to the Heart and more loath to let it out of his possession.

As the parties involved get closer to the rock, a confrontation is inevitable. And Picard must fulfill a destiny, even if it means overcoming his obsession.

This is Carmen Carter's last Star Trek novel to date, after a production of four. Her stories were usually off-beat, and this one sort of fits that bill. She often tells tales of a somewhat supernatural or mystical nature, and this is no exception. However, her writing in this book is somewhat repetitive, and the climax becomes an anticlimax. The ending is somewhat satisfying, but the promise of the premise is not fulfilled. On the other hand, the author seems to reach the conclusion she was attempting. A shoot-em-up ending is not the normal modus operandi of Carter. Instead, this one goes out with more of a whimper.

And that, in the end, may be the problem. The ending seems too easy, and there is no explanation of why this fragment of the Guardian of Forever would want such a disposition, as intimated in the plot. Not to give too much away, but the end did not make much sense to me. It was not emotionally satisfying. The reconciliation between Guinan and Camanae (Carmen Carter?) was nice, but not enough.

Can't really recommend this one. If you find it in a bargain bin or a library, a Star Trek fan might like it.