On the morning of Gail's birthday, she watches her shadow slip under the kitchen door. She's not surprised it decided to leave. Her dad has gone for good. Her big sister Kay, once Gail's best friend, has disappeared into sadness, and now her shadow has left too. Determined to make things right, Gail chases after the shadows. But her adventures take her to unexpected places and Gail discovers that where there are shadows, there's darkness, and she's not the only one looking for something missing. In a world of light and shadow, despair and hope sit side by side, can Gail recover what the sisters have lost?