Ultramarine is the story of Dana Hilliot's first voyage, as mess-boy on the freighter Oedipus Tyrannus bound for Bombay and of his struggle to win the approval of his shipmates, trying to match their example in the bars and bordellos of the Chinese ports while at the same time remaining faithful to his first love, Janet, back home in England. Alternating between Dana's own narrative and the ribald humor and colorful language of the sailors' conversation, Ultramarine depicts a boy's initiation into the company of men.