The Mystery Girl: Henry, Jessie, Violet, and Benny are working in a general store, to help out a friend of Aunt Jane's. It seems to the children that the young girl who works in the store is behaving very strangely. She seems nervous and won't answer any questions about her past. Then a strange man comes to the store asking about her. What secret is the mystery girl hiding?

The Mystery Cruise: The Aldens are on a cruise in the Caribbean! No sooner has the cruise begun than things start to go wrong. The ship's radio breaks. It appears someone has fallen overboard — but it turns out to be a false alarm. And then there's engine trouble! Is someone deliberately tampering with the ship? It's a mystery — good thing the Boxcar Children are on board!

The Disappearing Friend Mystery: The Boxcar Children decide to raise money to help the Greenfield hospital. At Beth's suggestion, they form a service called The Boxcar Helpers — to babysit, wash cars, mow lawns, and care for pets. But Beth keeps disappearing. And then other things start to go wrong. Is someone trying to put them out of business?