Nearly a decade after Captain Kirk vanished, his protégé, Captain Hiraku Sulu of the USS Excelsior, leads a dangerous mission into uncharted political waters. Unprecedented peace talks with the violently xenophobic Tholian Assembly trigger a deadly confrontation aboard the Excelsior. Now Sulu and his crew — including Chekov, Rand, Chapel, Tuvok, and Akaar — are thrust into an unexpected conflict between the Tholians and a mysterious new enemy, the Neyel... whose origins, if revealed, could lead to war with Earth itself.
As the Tholians weave a web of vengeance, the Excelsior is flung beyond the galaxy and the crew discovers the hidden truth about the alien Neyel, forcing Sulu to question where his responsibilities lie: with the fragile peace he must preserve, or with the victims of his own world's tragic past?