After he sees some unusual late-night deliveries, Martin's active imagination has him and his friends convinced that the man who has recently moved into the attic apartment should be watched.
Lily and her aunt, a Chinese American movie actress, join forces to solve the theft of some priceless pearls and stop the operator of a sweatshop in San Francisco's Chinatown.
Assisted by her cat Max, sixth grader Minnie starts up her new detective agency by investigating a kidnapping and a thief who will steal anything, even a hot stove.
When the Aldens visit Yellowstone they discover a map showing the way to an old cabin where gold is supposedly hidden, but they encounter lots of interference in their attempts to hike the trail.
