The adventures of the four Alden children as they spend a summer vacation on their very own island, purchased by Grandfather's father years ago.

When the Alden children go camping on Blizzard Mountain, a place said to be inhabited by a ghost looking for buried treasure, they begin to think someone or something is trying to scare them off.

Despite warnings and threats from a woman named Angela, the Boxcar children set out on a canoe trip with Aunt Jane and become involved in a case involving a mysterious riddle and a stolen coin collection.

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

A family, snowbound in a vacation cabin, discovers adventure in surrounding wild life, three children they find in the snow, and a search for a lost recipe.

When the Aldens spend the summer riding on a train, they get to live in a train car once again - this time, they're staying in Caboose No. 777. The number is hard to forget, and indeed, the children meet people at each stop who seem to know it well. It turns out Caboose No. 777 has an unusual past - one that comes with its very own mystery!

During a trip to New England, the Aldens learn about a mysterious ship, the "Flying Cloud," that had been lost at sea years earlier and that supposedly reappears during a storm

When the Aldens go to the Pickering Natural History Museum to assist with the opening of a dinosaur exhibit, their work is hampered by a series of mysterious happenings.

While staying at a hotel in New York City, the Aldens investigate a series of annoying pranks plaguing the management and guests

While investigating the disappearance of Mr. Woods' beloved cat, the Alden children uncover a number of mysterious suspects in the catnapping