Although Ruby seemed to just appear out of thin air on the steps of the courthouse on the first day of summer in 1944, no one in Way Down Deep, West Virginia, ever worried too much about where the toddler came from. They figured that if Ruby's people were dumb enough to lose something as valuable as a child, then that was their problem.

So even though Ruby can't help but wonder where she came from, she has led a joyful and carefree life in Way Down Deep, loved and watched over by Miss Arbutus - proprietor of The Roost, the local boardinghouse - the residents of The Roost, and the rest of the town. But when Ruby is twelve, a new family moves to Way Down Deep, and they inadvertently provide enough clues about Ruby's past that she is able to find her own people.

Ruby travels from Way Down Deep to the top of Yonder Mountain to learn who she really is - only to find that she is bound to Way Down Deep by something even stronger than family ties: love.