When the Aldens agree to watch the house of a local author who has written a book about a vampire, they end up investigating activities that are suspiciously similar to those in his book.

The Alden children stumble upon a mystery when they enter their dog, Watch, in a contest that could lead to fame and fortune, but where things keep going wrong.

When they take their dog, Watch, for obedience training, the Alden children discover that some of the dogs in the class have vanished and decide to try to solve the mystery of their disappearance.

A local radio station is holding the Great Detective Race, and the Boxcar Children have entered the contest! They solve riddles and search all over town for clues leading to the grand prize. But when some of the clues turn out to be fake, it's clear that someone is playing unfairly! Who could be trying to ruin the race - and why?

The Aldens help out at a medieval fair and try to find a valuable sword which has been stolen from the fair.

The Alden children visit a family friend at his apple orchard which is rumored to be haunted, but instead of a ghost they find that some of the families' valuable antiques are being stolen.

Relates the exploits of the four Alden children as they locate a missing man. The Boxcar children are determined to solve the mystery that surrounds an old yellow house on their grandfather's property. Strange things have happened in that house where long ago a man disappeared.

Henry, Jessie, Violet, and Benny are on a train from Boston to San Francisco. Even though they used to live in a boxcar, this is the first time they've ridden a real, moving train. And they find a mystery to solve even before they leave the station. Is someone trying to steal a young woman's portfolio? Could it be the porter? Or is it the tall, bearded man who always wears sunglasses -- even at night? What's in the portfolio, anyway? Can the Boxcar...

The Aldens investigate when the arrival of several suspicious characters in Greenfield coincides with a mystery involving a popular boy actor.

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.