A British doctor explores how organ donation and transplant permanently intertwined the lives of two families. Nine-year-old Max was the last person anyone thought would need an organ transplant. However, when a virus invaded his body and fatally damaged his heart, Max took his place on a list of children awaiting organs. Nine-year-old, Keira was fatally injured in a car accident. This is the story of how her heart found its way into Max’s chest just in time to save his life. | 
