Holly Hotel and Lost Karin were two earlier books telling of adventures in the Scottish moors. Now comes the third mystery --not perhaps as spontaneous and realistic as the other two, but youngsters who like mysteries in which a group of enterprising youngsters solve a puzzle that baffles their elders, will enjoy it anyhow. The basis of the mystery in this story concerns itself with the strange terms of a will and an old and mysterious nearby castle, with gloomy halls, hidden doorways, and frightening rooms of doubtful occupancy. The ingredients are here for a spine chiller. The pace- and the solution aren't quite up to the stage properties.