Peony has traded one Hell for another. As a qualified doctor who only ever dreamed of helping people, being kept as a slave and then sold as breeding stock for Mortus demons was never on the cards. Freed from imprisonment, Zadkiel is an angel on a mission: find Heaven's stolen Heart and save the demon who helped him when he was a captive. But Z is suffering from a mystical illness no one can cure… Can he stay alive long enough to achieve his goals? Together, Peony and Z will need every ounce of their combined strength to survive the Mortus stronghold and find the key to Heaven's Heart.