After being left by the side of a road with nothing but her favorite sock toy, Tupelo meets a pack of dogs led by Garbage Pail Tex as they are wishing for new homes, then joins them as they catch a passing train and share stories of dog heroes.

"When he graduated from Harvard Medical School, Jim O'Connell was asked by the medical school dean to spend one year setting up a program to care for the homeless population in Boston. It became Jim O'Connell's life calling, to help people known as "rough sleepers." For the past three decades, Dr. O'Connell has run the Boston Healthcare for the Homeless Program, which he helped to create. Affiliated with Massachusetts General Hospital, the program...