Before they were the Boxcar Children, Henry, Jessie, Violet, and Benny Alden lived with their parents on Fair Meadow Farm. Although times are hard, the Aldens are happy - “the best family of all,” Mama likes to say. One day, a blizzard hits the countryside, and a traveling family needs shelter. The Aldens take them in, and the strangers soon become friends. But things never stay the same at the farm, and the spring and summer bring events that will forever change their lives.

The Aldens are spending their first week of summer at Camp Quest in Colorado. The children are excited to learn about fossil-hunting and paleontology from renowned scientist Dr. Iris Perez. But strange events at the camp make them wonder if the legends of a bigfoot-like creature roaming the valley might be more fact than fiction. Can the Aldens help Dr. Iris figure out who - or what - is causing such a stir?

The Boxcar Children tells the story of four orphaned children, Henry, Jessie, Violet, and Benny. They create a home for themselves in an abandoned boxcar in the forest. When a local baker and his wife learn that the children are orphans, they plan to send the children to live with their grandfather, but the children have been brought up to fear their grandfather, whom they have never met, because he did not like their parents' marriage. But their grandfather turns out to be a wealthy and kind man.

Henry, Jessie, Violet, and Benny didn't think the old trunk in their house held anything interesting. But an unusual statue they find inside leads them to the Reddimus Society, a secret guild dedicated to returning lost treasures to where they belong. Now the Aldens must help their new friends by traveling across the country with the statue and six mysterious boxes! Can the Boxcar Children keep these seven treasures out of the wrong hands?

When an oil spill takes place off the coast of Connecticut, the Aldens are happy to volunteer to help clean up the animals affected, including a rare species of shore bird. But could more have been done to prevent the spill? As the Aldens take up the case, it leads them on an adventure to help other endangered animals around the world.