Four orphaned children make a home for themselves in an abandoned boxcar and are united with their grandfather.

The children are staying at the home of a famous inventor who was known for her one-of-a-kind clocks. All the clocks make noise especially at midnight, when there are enough chimes, gongs, and clangs to wake thw whole house up! But the clocks aren't the only sound in the house at midnight. Someone or something is making a mysterious tapping sound. Who could be inventing trouble in the old house?

When Grandfather's friend Charlotte bought a mysterious mansion known as Skeleton Point, she invited the Alden children to help her fix it up.

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.

Benny anticipates making friends with the new kid down the street, but when he finds out that she's a girl, he is very disappointed.

The Aldens are excited to be playing in their summer soccer league, until someone begins sabotaging the teams.

When the Alden siblings visit their grandfather's friend in an apartment building, they begin to wonder about the many mysterious events that keep happening on the thirteenth floor of that building.

The Aldens investigate when the new coach of their community basketball league has her Most Valuable Player trophy stolen.

The Aldens visit Grandfather's friend at the Ogopogo Retreat and aided by puzzling clues, embark on a treasure hunt to prevent the retreat from being sold.

A series of practical jokes at a restored nineteenth-century farmhouse makes the Aldens wonder if the ghost of its builder is at work.