McIntyre, Vonda N

An alternate history in which Marie-Josephe de la Croix, the sister of a Jesuit priest in the employ of France's King Louis XIV, befriends a sea monster the monarch believes holds the key to immortality, and draws the wrath of the king by attempting to set the captive creature free.

At long last, Admiral James T. Kirk and the "Starship Enterprise" crew begin their long journey home, but when a mysterious, threatening intruder appears, they must embark on one more mission--through time--in order to save both their past and their future.

Captain Kirk was the youngest man to captain a starship in Federation history.