When, as the new Classics professor at Vandemark College, their father is made responsible for a collection of ancient Egyptian artifacts, twelve-year-old Phineas and his older sister Althea try to find out why the collection is the target of thieves, especially when the mummy disappears.

While camping on Crab Island in the British Virgin Islands, twelve-year-old Sally and her two younger brothers rescue an injured dolphin and become involved in a dangerous adventure with mysterious strangers.

The Alden children have another mystery to solve when they visit a castle and must figure out which of the guests has stolen the Stradivarius violin.

While exploring the caves around Dragon's Mouth Cavern, a series of unusual and somewhat frightening events convinces the Alden children that someone does not want them around.

The Aldens are excited to be playing in their summer soccer league, until someone begins sabotaging the teams.

The Boxcar children investigate when ice cream and other items start disappearing from their favorite ice cream parlor.

When they help out at a guide dog training school, the Alden children meet several people who seem obsessed with a particular dog named Ginger.

The Alden children draw upon their resourcefulness to save the neighborhood firehouse from being torn down, while they also face a series of mysterious incidents connected with it.

While sightseeing in San Francisco, the Boxcar children uncover a mystery involving fishing boats and sabotage.

The Alden children investigate when Mrs. Murray's jewels are stolen during a party for the Starlight Skating Troupe.