Following the explosive events of Star Trek: Nemesis, the Romulan Star Empire is in disarray, and Ambassador Spock attempts to render aid by launching a last-ditch effort to reunify the Romulans with their distant forebears, the Vulcans. But when Spock is publicly assassinated at a Romulan peace rally, Starfleet and the Federation are unable to search for the criminals responsible without triggering an intergalactic war.