Cam, her best friend Eric, and Eric's mom are spending the day with Eric's grandparents. But Grandpa and Grandma seem too tired to visit. Every so often, a knock at the door wakes them up. But when they go to answer, no one is there. Is a Knock, Knock Ghost on the loose? It's up to Cam to solve the mystery Garden State Children's Book Award 2017 Nominee.
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