Ghosts and a history lesson bring out an American teenager's long-suppressed grief in this engaging, but overstuffed, debut. Visiting Wales with her medievalist father Derek, Cristyn shares a bedroom with Miranda, daughter of another historian, Erica. Barely have the two families moved into their old cottage before the manifestations begin: dreams and noises; apparitions in the cellar; furniture, Scrabble tiles, and Cristyn's picture of her long-dead mother moving about; and more. The ghostly drama, however, competes with family drama for the front seat. Miranda, in the wake of her parents' divorce and unaware that her father had tried to kidnap younger brother, Dennis, is angry at the slightest provocation; meanwhile, Dennis has taken to playing pranks to get attention, as Erica straggles to keep both of her children in the dark about her ex-husband (he shows up later, just long enough to prove his worthlessness). Cristyn tries to make peace between Miranda and Dennis, puts the ghostly doings to rest, and sits down with her father for a healing talk about her mother. Kimmel shows promise with dialogue and characters; Cristyn's wry sense of humor, plus an occasional peer conversation in teenspeak, lighten the general tone. The problems: A ghost, daughter of a 13th-century rebel, is uncommonly able and rational (with a good command of modern English), and the various plot lines are so weakly joined that they're all but independent.