This is the story of sixteen year old Jo Larson, whose sister is her only living relative, or so she believes. Jo has a secret: she is suffering from a rare form of childhood leukemia. While waiting for a miracle, she watched time slip away. But older sister, Kate, is not giving up. When the miracle finally arrives, it comes unexpectedly: bone marrow sealed with angelic DNA from a mysterious relative of the father they never knew. After Jo survives an induced angelic ritual, Jo and Kate decide to abandon their old lives in search of happiness.