Horse story addicts may be able to wade through the melange of plot twists, the characters stereotyped to the point of grotesquerie, and the ghostly elements of enchantment which tend to overwhelm this story of a twelve-year-old girl and a ""rare miniature horse"" she calls Hobbit. Mary Ellen and her cousins Adele (""Ed,"" a tomboy with a passion for stables) and Alice (a fantasy-ridden, manic depressive sort) are to spend some time at their grandparents' estate in Pennsylvania on the edge of the Main Line, with the dying grandmother choosing one of them as her heir, since her children (their parents) have all disappointed her. One of them, Clinton, died in a fall from a horse as a young man; he haunts the estate, and his son, never acknowledged by the grandmother, haunts it in the flesh with his hawk and ferret. At the county fair, Mary Ellen buys Hobbit out of pity, since he's destined to be butchered otherwise, but due to her grandmother's aversion to horses she must hide him in the ghost-tenanted nursery. The animal business is so appealingly handled it's a shame that it is lost in a muddle of too much pseudo-psychiatry and occultism. But a miniature horse, no matter how rare, can carry only so much.