Ava, Ellie, and Griffin are very fortunate children. They have families, friends, a nice school, and enjoy many privileges in their lives. When a classroom speaker tells them about the Orphan Train, they become interested in the children who rode the train in search of loving families. After learning that not everyone who adopted children treated them well, the kids are angered and decide to do something about it. The three friends convince Miss Snoddy to take them back in time to purchase tickets on the Orphan Train so they can protect innocent children from evil-doers.

Everything goes as planned until the unthinkable happens and their friendship is threatened. Ava, Ellie, and Griffin must dig deep and trust in each other, Miss Snoddy, and new friends in order to survive.