Marty had just finished burying a dead robin near the tall wooden fence that surrounded the Hutchinson back yard and the house next door. Suddenly she heard it⁠—knock, knock, knock⁠—three knocks coming from the other side of the wall. For a moment Marty was too petrified to move. Knocking on a wall was something a crazy person might do and some people said old Mrs. Hutchinson was crazy, living alone with an unmarried daughter and seeing no one. Then the knocks came again.

Marty soon learned the identity of the person on the other side of the ten-foot wall, and why she stayed there. What was harder to discover was a way to help her new yet unseen friend. For a long time all Marty could do was communicate through the wall and be patient. It was not until a deadly flu epidemic gripped the town and Marty could not come to the wall that her friend finally dared to step outside it.

Evoking small town life in Oregon during World War I with vividness and a clear sense of time and character, Evelyn Sibley Lampman has created a very human and dramatic story that will carry its readers along to a most satisfying conclusion.