Four orphaned siblings, determined to stay together as a family, decide to inhabit an abandoned boxcar and turn it into their new home in the woods. When one of the siblings falls ill, the others go out to seek a doctor to save their sister. Meanwhile, their wealthy grandfather has offered a sizable reward to anyone who has information about his grandchildren, hoping that they can all be reunited once more. As the children continue to evade being...

The Alden's neighbor, Lina, thinks there's treasure hidden in her attic and she wants the Boxcar Children to help her find it. Of course, the children are eager to help search—but it appears they aren't the only ones looking for the treasure.

When an elderly friend is injured, the Alden children offer to help him with his window-washing business in their small town of Greenfield and agree to help him solve a riddle that has arrived in a mysterious invitation.

The Aldens are spending a week at Camp Seagull on beautiful Claw Island. But as soon as camp begins, they realize that someone is not playing fair. Everything begins to go wrong for the Aldens they lose their luggage, Henry misplaces the camp flag, and the campers on the other team use one of Jessies ideas to score points for themselves. Are some campers so desperate to win the Olympics that they are willing to cheat? The Boxcar Children are...

Two brothers take summer jobs at a department store where a series of peculiar events brings them under suspicion.

While visiting an old mansion, the Aldens investigate the possibility that it may be haunted.

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.

The Aldens visit an old Kansas inn that's full of secrets! Nobody knows why a famous photographer visited the inn just to take a single picture. And what about the other legendary guest--a heroic young stranger who'd come west on an "orphan train?"

The Aldens participate in a three-day bicycle ride and soon find that someone seems to be intent on keeping others from completing the event.

When their favorite author fails to arrive as scheduled to speak at the local library, the Alden children investigate how he could board a train and never be seen again.