The third installment in Becca Fitzpatrick's four-book
Hush, Hush saga, the novel is set in Coldwater, Maine, in a world where fallen angels coexist with humans and Nephilim, an immortal race descended from the union of fallen angels and humans. Each year during the Jewish month of Cheshvan, fallen angels possess the bodies of Nephilim who have sworn oaths of fealty to them. A prologue set three months before the main story establishes the central conflict. Hank Millar, a powerful Nephil known as the Black Hand, has kidnapped Nora Grey, a teenage girl, from Delphic Amusement Park and holds her captive to coerce her boyfriend, a fallen angel named Patch, into spying on other fallen angels. Hank wants to prevent fallen angels from possessing Nephilim during the coming Cheshvan as part of his plan to build a Nephilim army. In a cemetery at midnight, Patch attacks Hank but is subdued. Desperate, Patch offers to let Hank's men tear out his wings in exchange for Nora's release by summer's end. Hank swears a blood oath, and the wings are ripped out. Afterward, Hank calls Nora's mother, Blythe Grey, feigning ignorance and promising to help find Nora.
The main narrative opens in September. Nora wakes on a grave in the cemetery with no memory of how she got there and no recollection of events past the previous April, five months completely erased. Detective Basso finds her and informs her she has been missing for eleven weeks. At the hospital, Dr. Howlett diagnoses retrograde amnesia, explaining that Nora's mind is blocking traumatic memories. Released, Nora reconnects with her best friend, Vee Sky, who recounts the night of Nora's disappearance: They went to Delphic, gunfire erupted, and a fallen angel named Rixon held Nora hostage in the park's mechanical room before she was released. Rixon then vanished without a trace. Nora is haunted by recurring flashes of the color black and a whispered voice calling her "Angel." She finds a large black feather in the cemetery that stirs a deep sense of connection she cannot place.
Returning to school, Nora faces pitying stares and troubling revelations. Her mother is dating Hank Millar, the recently divorced father of Nora's long-standing rival, Marcie Millar. Nora learns she was shot in the shoulder at Delphic and that Scott Parnell, a childhood acquaintance, dropped off a replacement car the night she vanished. At a dinner with Hank, Marcie corners Nora and mentions a former boyfriend named Patch who gave Nora a necklace. The name triggers an intense jolt of recognition Nora cannot explain.
After leaving the restaurant, Nora witnesses a violent confrontation at a convenience store where a fallen angel named Gabe tries to force a clerk to swear a fealty oath. A fallen angel named Jev, whose presence triggers the same flashes of black that haunt Nora, intervenes and rescues her. Gabe survives a seemingly fatal wound, confirming he is not human. Jev claims he and Nora met five months ago and that he hurt her, but she senses he is lying. When she accidentally touches his bare back, she is hurled into a vision of Jev and Hank arguing over a caged archangel, a high-ranking angel. The vision ends violently, and Jev vanishes.
Scott Parnell tracks Nora to the coast and reveals the hidden world beneath Coldwater. He demonstrates his Nephilim immortality by stabbing himself; the wound heals instantly. Scott identifies Hank as the Black Hand and reveals that Rixon killed Nora's father, Harrison Grey. He also identifies Patch as Nora's ex-boyfriend, not Marcie's summer fling as Marcie claimed, and proposes they work together to expose Hank.
Nora breaks into one of Hank's warehouses and discovers it is a Nephilim barracks housing hundreds of Hank's soldiers. Jev rescues her and brings her to his underground studio beneath Delphic, where she learns the truth by touching the scars on his back where his wings were torn out. The scars serve as a window into his memories; through them she discovers that Jev is Patch, operating under an alias, and that Patch struck a deal with Hank to spy on fallen angels in exchange for Nora's life. She also learns that Hank is holding a captive archangel and hunting for Patch's archangel's necklace, a relic with the power to compel any archangel to speak the truth. Nora and Patch reconcile and begin plotting against Hank together.
Hank then engineers a car crash to render Nora unconscious, using the interval to secretly perform a blood transfusion that floods her veins with his purebred Nephilim blood. Dr. Howlett, Hank's ally, conceals the procedure at the hospital. Hank ultimately captures Nora and her mother and reveals what he has done, demanding that Nora swear a Changeover Vow to become a purebred Nephil and lead his army upon his death. He also confronts Nora with the black feather retrieved from her room—Patch's own feather from the night his wings were torn out—warning her that burning it would chain Patch in hell forever. To save her mother's life, Nora swears the vow.
Simultaneously, Patch recruits Gabe and two other fallen angels to raid Hank's warehouse and free the captive archangel. Patch persuades the archangel to petition heaven using his own archangel's necklace, and the archangels—eager to stop Hank's use of devilcraft, a forbidden power drawn from hell—sanction Hank's death. When Patch prepares to execute Hank in his underground cell, Hank produces Patch's black feather and threatens to burn it, an act that would chain Patch in hell for eternity. To protect Patch, Nora shoots Hank dead.
The novel closes on an uncertain note. With Hank gone, his Nephilim army is in chaos. Scott returns with two of Hank's senior lieutenants, reminding Nora that her sworn vow compels her to lead the rebellion against fallen angels. If she refuses, she and her mother will die for breaking the oath; if she declares war, she risks catastrophic conflict with the archangels who authorized Hank's death. Standing beside Patch, Nora faces a future in which war between Nephilim and fallen angels appears inevitable.