The story is set in an alternate 1940s Chicago in which magic exists. Helen Brandt is asked to investigate a murder scene using her supernatural abilities. Helen has approximately three days to live, as her
deal with the devil comes due. Despite this, she agrees to investigate. The victim has been killed by the White City Vampire, a
serial killer who drains his victims’ blood and uses it to paint sigils at the scene. Helen is confronted by her estranged brother Theodore “Teddy” Brandt, a member of the Order of the Compass. Helen has been cast out of the Order for bargaining with the devil. Helen meets up with her partner, Edith. Helen has not yet told Edith about her limited lifespan. While Edith plans to move to
San Francisco, Helen knows that this is merely a dream. Helen then meets her client Marlowe, the woman who hired her to investigate the murder scene. Marlowe reveals herself as a
demon and offers to return Helen’s soul in exchange for identifying the Vampire. Helen learns that the victims of the White City Vampire were all people who had made Faustian bargains in the past. The souls were promised to Marlowe, but another demon has stolen them; Helen is now involved in a demonic turf war. Teddy and Helen meet up at the crime scene. A flashback reveals that Helen made her deal with the devil after Teddy was killed in a car accident. The deal allowed for Teddy’s resurrection at the cost of Helen’s soul, which would be collected after ten years. That night, Edith returns home but speaks with a new voice. Helen learns that Edith is the willing host for Haraniel, a
fallen angel hoping to restore their place in heaven. Together, Haraniel (in Edith’s body) and Helen go to the local zoo, where another murder has just occurred. They deduce that Matilda, a local girl, was possessed by the Vampire when she committed the crime. Helen and Haraniel visit Matilda in the asylum where she is being held. After interviewing her, they realize that the Vampire is actually an angel who uses hosts to murder their victims. Haraniel reveals more about the history of angels. When the
Watchers sired the
Nephilim with humans, God recalled the angels to Heaven. Some returned and were forgiven. Others refused, and the way to Heaven was closed to them. They remain on Earth, hoping that bonding with human hosts will allow them to reach Heaven upon the host’s death. The Vampire hopes to use the power of the stolen human souls to summon
Michael, who will open the way to Heaven once more. Members of the Order kidnap Teddy, planning to use him as the Vampire’s final host. The Vampire is revealed to be Zashiel, an angel who is hosted by Edith’s priest. Zashiel has lost faith that human hosts can bring fallen angels to Heaven. He has decided to summon Michael and open the way himself. Helen summons Marlowe to fight Zashiel. She fulfills Marlowe’s bargain, gaining control of her soul once more. In the conflict, Zashiel kills Edith. Teddy kills Zashiel’s host, damning himself to hell. Helen asks Marlowe to bring Edith back to life, once again selling her soul to the devil in ten years’ time. Edith returns to her body, leaving Haraniel in Heaven. Edith and Helen promise to spend the next ten years together. ==Reception and awards==