The Boxcar Children are helping out at a pizzeria. The pizzeria is run by their old friends the Piccolos, whove been having lots of troubles keeping their business going. Working at the little restaurant is so much fun, but the children wonder . . . is someone deliberately trying to shut down Piccolos Pizzeria?

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!

The Alden family rents a houseboat to drift down the river, and encounters a mystery in the little towns along the river, involving a fast black car.

A young Canadian visitor helps the Alden family solve a mystery involving a lost coin collection.

A rockslide strands the Aldens on a mountain! But being stuck on Old Flat Top isn't all bad. As the children wait for rescue, they discover that a secret cave has opened up―one that just might hold legendary treasure!

The Aldens head back to Mystery Ranch for another summer! They are thrilled to learn their friend Mike has moved to Yellow Sands―a new town nearby. But when a house fire breaks out and Mike is blamed for starting it, the Aldens must find the real culprit to help their friend.

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.