Margo is determined to help her sister fall in love, but when she finds out her sister likes Daniel, the school’s resident bad boy, she vows to keep them apart even if it means getting close to him. Daniel spent his entire childhood feeling abandoned and unwanted until Margo, a girl who suddenly refuses to leave him alone, disrupts his life. He finds himself slowly falling in love with her, but he doesn’t know her secret… Margo is dying.