Gr 5-7 Lonely, precocious Cassandra, a motherless seventh grader, finds a mentor and special friend in English teacher Ms. Schuyler. Her fantasies of promoting a match between her widowed father and Ms. Schuyler lead to familial tensions and a cruel confrontation with the woman for whom her father really cares. After the damage has been done, Cassandra's out-of-hand repudiation of the teacher who has been unwilling to play her ``assigned'' role and her switch to her own concerns in the form of a budding relationship with a male classmate make for a believable denouement. In her characterizations and plot, Ames deftly charts the quicksilver phases of teen developmenta mix of dependency, self-absorption and rebellion. A strong story, beautifully told and thought-provoking. Libby K. White, Schenectady County Public Library, N.Y.