[back cover blurb] A hundred years before the Starship *Voyager* was transported to the Delta Quadrant, Lieutenant Tuvok served under one of the Starfleet's most famous officers: Captain Hikaru Sulu of the Starship *Excelsior*. Now those days have come back to haunt him. While travelling through an uncharted nebula, Tuvok is besieged by recurring memories of his time with Captain Sulu -- repressed memories that may well kill him unless their source is determined in time. To save her closest friend, Captain Kathryn Janeway follows Tuvok to the century-old bridge of the *Excelsior* during a desperate battle. There Tuvok, Captain Janeway, Captain Sulu and Commander Janice Rand must face a menace to galactic life unlike anything known before....