When the Wolf Comes Home

When the Wolf Comes Home (2025) is a horror novel by American author Nat Cassidy. The novel follows Jess Bailey, a down-on-her-luck actress who crosses paths with a young boy on the run from his father. When Jess discovers that the boy and his father have unusual abilities that leave a toll of death and destruction in their wake, Jess is forced to flee across the country and bring the boy to safety. The novel explores the themes of The Struggle to Be Brave, Navigating Familial Cycles of Violence, and Nature Versus Nurture.

Cassidy wrote the novel to process his relationship with his late father. The book forms an informal trilogy with his two previous books, Mary: An Awakening of Terror (2022) and Nestlings (2023), which discuss personal loss and grief.

This guide refers to the paperback edition published by Tor Nightfire in 2025.

Content Warning: The source material and study guide feature depictions of death, child death, graphic violence, child abuse, suicidal ideation, mental illness, disordered eating, addiction, substance use, and cursing.

Plot Summary

Jessa Rae “Jess” Bailey is a 31-year-old aspiring actress who works the night shift at a diner in Los Angeles, California. She is grieving the death of her estranged father, Tommy, which distracts her while she is cleaning the diner bathroom. She accidentally pricks her finger on a used syringe, which causes her to panic and leave work early.

While going home to her apartment, Jess tries to work out her next steps. She learns that she will need to see a doctor within 72 hours of exposure. Before she can leave for the hospital, she encounters a runaway boy carrying an illustrated storybook of fairy tales. Shortly after taking him in, she and her apartment neighbors encounter a strange man who transforms into a monstrous creature. The creature slaughters many of Jess’s neighbors, forcing her to escape with the boy. The boy indicates that the creature is his father. During the escape, Jess accidentally shoots a police officer responding to the emergency.

Jess shelters the boy at the house of her older coworker, Margie. She makes plans to escape with the boy to the retirement home where her mother, Cookie Montgomery, lives in Scottsdale, Arizona. While Jess returns to the diner to retrieve her cell phone, the strange man tracks the boy’s scent down to Margie’s house. Margie is killed when the man transforms into a creature once again. The boy narrowly escapes using a blanket that he is convinced gives him powers of invisibility. He reunites with Jess, and they head east.

Cookie instructs Jess to check in at a Radisson hotel not too far from her retirement home. This gives Jess and the boy a moment of reprieve, during which Jess learns that the boy doesn’t know his own name. She convinces the boy that she is a famous actress and then leaves him in the hotel room to watch the film Who Framed Roger Rabbit on television while she goes to the clinic. When she reaches the clinic, she is surprised to learn that everyone recognizes her as a famous celebrity. She flees back to the hotel, which is under attack by the animated villains from the film that the boy was watching. Jess realizes that the boy has the ability to manifest whatever he believes into reality. She uses this to help them escape the hotel.

FBI (Federal Bureau of Investigation) Agent Michael “Mickey” Santos is sent to retrieve the boy from Jess. He learns that the boy and his father, both named Peter Calvert, are the result of a failed military experiment intended to produce enhanced soldiers. Santos’s research leads him to Cookie, whom he decides to visit in the hopes of learning Jess’s whereabouts.

Jess drives the boy to Scottsdale, reflecting on his powers and the risk they pose on their journey. At one point, the boy’s powers bring chaos to a Target where Jess stops for supplies. She scolds the boy for failing to control his powers but becomes sympathetic to him when he describes himself as being “too bad to be alive” (124), as his father claimed. They stop at a motel before reaching Scottsdale. To pacify the boy, Jess gives him a sleeping pill that unwittingly causes him to experience vivid nightmares.

Santos convinces Cookie that he will keep Jess safe from prosecution. Cookie is still cautious and is further puzzled by a visit from another man who claims to be a casting director looking for Jess. When Santos arrests the “casting director,” he discovers that he is none other than the adult Calvert, who transforms into another unstoppable creature. The creature massacres Cookie’s bridge party before making its way to Cookie herself. Cookie directs Jess to Pennsylvania to reunite with her relative, Uncle Pepsi. Before she dies, Cookie pleads with Jess not to hate her.

Grieving, Jess drives the boy to Pennsylvania. She and the boy talk about how she learned to overcome fear by getting into improvisational comedy. She says that they are alike in that they are both afraid of the world all the time. When they arrive, Uncle Pepsi shows them around the cabin, which Jess learns was her father’s final residence in the years before he died. Jess discovers letters that Tommy attempted to write to her but never sent. While reading the letter drafts, she learns that Tommy abandoned her as a child because he had an alcohol addiction, which caused him to neglect Jess and put her in two life-threatening situations. Jess continues to resent her father, albeit with a greater understanding of his anxiety around her.

Jess considers how she can protect the boy when his powers are out of her control. When she finally visits an urgent-care clinic to take a blood test, Santos finds her. He survived the attack on Cookie’s condo and traced Jess to her father’s last-known residence. Santos tells Jess that he can bring the boy to scientists who will cure him of his abilities. When Jess realizes that the boy’s powers are what cause the adult Calvert to transform into a creature, she becomes convinced that there is no other way to protect the world from the boy’s powers.

The boy isn’t happy to see Santos, which makes Jess think twice about her decision. When Santos draws his gun on Jess, Jess orders the boy to make Santos disappear. This violently erases Santos from reality. Horrified by his actions, the boy flees from Jess, making himself invisible from her. Jess convinces him that there is still time to become more than the “bad kid” he thinks he is. They are soon intercepted by Calvert, who has transformed once again into a giant wolf. The ensuing chase takes them back to the cabin, where Jess wounds the creature’s eye. She gets the boy to transform a host of baseball caps into bats, overwhelming the creature.

Calvert reverts to human form, prompting the boy to reconcile with him. Their reconciliation is thwarted when Calvert shoots his son, unsure of how else he can protect the world from the boy. Jess tells Calvert that he only succeeded in proving the boy’s fears of his father true. She shoots Calvert.

Jess is brought back to Los Angeles by the FBI. While staying at the same hotel she visited with the boy, she receives her blood-test results from the clinic, which read “positive.” Jess avoids reading the rest of the result for as long as she can.

That night, she discovers that she has inherited the boy’s power, as she manifests visions of Tommy, Cookie, and the boy as shadows and corpses. Jess’s visions convince her that her new powers ultimately caused the boy’s death. She escapes from them by transporting herself to a backstage room, much like the one she performs improvisational comedy on. She encounters a younger version of herself, who convinces her to be brave and accept that she is capable of undoing all the bad in the world. Jess believes in herself and uses the power to make her infection go away. On the stage, she feels home again.