Echoes of Brideshead Revisited in this British first novel mourning the loss of innocence and love in settings as baroque and evocative as Waugh's. In luminous but mandarin prose that gives this story, set in postwar England, a slightly archaic flavor, the 50-ish narrator, Thomas Lamb, tells the story of how his ``own destruction began in a seedy hotel in Venice not quite overlooking the Grand Canal.'' Here Lamb was conceived, and though mother Dorothy married Toby Lamb, Thomas is not certain Toby is his father. Toby, who never lived with them, disappeared for months, even years at a time, before reappearing to regale mother and boy with tales of his adventuresadventures that usually included his friend, the larger- than-life aristocrat Henry Usher, who mysteriously disappeared in 1956. Thomas and his mother live in a caravan in the garden of the house belonging to Frankthe husband of Dorothy's twin sister, Mary, and the putative father of cousin James, born just six hours before Thomas. The boys are close in spirit if not looks, for James resembles a ``Young Lochinvar'' while Thomas has a disfiguring birthmark on his neck. In the summer before the two begin college, Toby takes them through France and Austria to Venice, Toby making intriguing comments about his past, and the two boys having their first sexual experiences. Back home, Thomas makes love to Netta, his childhood sweetheart, but his happiness ends when James, after discovering his real father, is killed in an accident in Oxford. The subsequent years are blighted by grief and an obsessive need to learn the truth about his father. Though the old and ailing Toby makes a stunning confession, Thomas, in Venice, finally unravels a major part of the story. A beautifully crafted story with a fine mystery at the centerbut echoes of a masterpiece can never offer a vibrancy and energy like those the first time around.