Seventeen-year-old Sebastian Barnack, a handsome and precocious poet, travels from his native England to Italy for the summer. There, he has his first love affair, becomes involved in the theft of a valuable painting, and falls under the influence of two men--his father's cousin, Bruno Rontini, a religious bookseller, who teaches him about things spiritual; and his Uncle Eustace, who introduces him to the hedonistic life.