Allie Nichols has hardly laid the last spirit to rest when she’s sure that another one is trying to reach her. But how can Allie help a ghost who won’t speak? All she has to go on is a sound—a sort of whine—and a smell. At the same time, a strange boy joins her sixth-grade class. Allie doesn’t understand why L.J. Cutler would start a new school at the end of the year, or why he’s such a surly kid. She wants nothing to do with him. Then Mr. Henry, a teacher she loves, asks Allie to dog-sit Hoover, his golden retriever, while he’s away and to befriend L.J. over the summer. She’s delighted to spend time with Hoover, but she hardly looks forward to visiting L.J. Cutler—until she discovers a connection between L.J., the ghost, and Hoover.

When Allie is contacted by the ghost of a dog, she and Dub investigate the surly new boy at school and his father, who may be running a puppy mill, to see if they are involved.