Four orphaned children run away and live in a boxcar, until they are found by their grandfather. Includes a biography and photographs of the author.

The Aldens have joined Dr. Iris Perez as she investigates legendary creatures around the world. In this adventure, the children investigate what might be living in the deep trench off the coast of Puerto Rico. From manatees to mermaids to sea monsters, creatures of the sea have been attracting tourists to the area for years. But when a man on a nearby island goes missing, it's up to the Aldens to sort out fact from fiction.

The mysterious disappearance of a reclusive neighbor's cat involves the Boxcar children in some complicated detective work.

While visiting the seaport town of Ragged Cove, Massachusetts, the Alden children find the ship's log of the Flying Cloud, shipwrecked in 1869, supposedly during a mutiny.

While canoeing and backpacking near Timberwolf Lake, the Aldens receive strange warnings to stay away from the area and stumble upon clues to a missing cache of stolen coins.

The Alden children plan to ride in their boxcar at the Greenfield Founders' Day Parade, but the newly refurbished boxcar is stolen a couple of days before the big event.

The Alden children suspect that the other guests are somehow involved when things begin to disappear at the bed and breakfast where they are staying in Washington, D.C.

While on bicycle trip to their aunt's farm, the four Aldens help solve a mystery.