From the shadows of the pool, Black as midnight, thick as gruel... Is Mrs. Tuggle a witch? Lynn and Mouse are sure she is - how else can you explain the frightening things that have been taking place over the past several months? Now Lynn's mom is planning to move her writing studio into Mrs. Tuggle's house for the winter, and Lynn can't imagine a more dangerous situation. If she and Mouse don't do something, there's no telling what horrifying things may happen. They've got to save lynn's mom before Mrs. Tuggle strikes again -- but how?