In all thirteen years of Anna's life, her parents have never given her a choice : she was born to be her sister, Kate's, bone marrow donor, and she has given Kate everything she needs. But when Anna is told Kate needs a new kidney, she begins to question how much she should be prepared to do to save the older sibling she has always been defined by. So Anna makes a decision that will change their family forever - perhaps even fatally for the older sister she loves.
