While staying at the Crooked House, the family home of their housekeeper Mrs. McGregor, the Aldens try to solve a riddle that will lead them to a hidden treasure.
Fifth-grader Cam uses her photographic memory, with help from her friend Eric and his twin sisters, to solve the mystery of Poochie, a famous canine television star.
Trying to be detectives, Mary Lou and her friends imagine that terrible crimes are being committed when Leroy, the worst kid who ever lived on Eighth Avenue, returns to the house next door.
While speaking at a crime writers conference, bumbling detective John Quincy Jones is aided by his capable canine in solving the mystery of two missing manuscripts.