Horror is a tricky genre. Too often, authors working in this mode resort to shocks and unexpected twists for their scares. Truly effective horror, by contrast, is unsettling. It has a human element that relies not on shopworn tactics or supernatural frights, but rather a slow tiptoeing toward the inevitable. Done right, horror is less a mood and more a character in and of itself, one that grows and takes shape as the bodies pile up.

In The Summer Is Ended and We Are Not Yet Saved, Joey Comeau steeps the horrific elements in a brew of emotional vulnerability and abuse of trust. The novel follows 11-year-old Martin and his mother, Elizabeth, who was only 18 when he was born. By day, Elizabeth works at the cosmetics counter in a Halifax department store, but her true passion is doing makeup for horror movies.

Martin and Elizabeth have a special bond forged in their shared passion for the macabre: their conversations involve subjects such as dangling kitten eyeballs and devouring the offspring of their enemies. However, their lighthearted banter masks Elizabeth’s darker instabilities: when she drinks she becomes reckless and bemoans having had a child at such a young age. Martin – sweet, innocent, and just a little bit naive – is her rock. He doesn’t need to know the details behind her strained relationship with her parents, or why she chose atheism over Christianity; he just needs to be there when she needs him most.

The story begins when Elizabeth is given the opportunity to travel to Toronto to work on the film Blood Socket 2. She needs to quickly find a place for Martin to stay while she’s away. With no one willing to help, Martin takes matters into his own hands: he calls his grandparents and asks them to enrol him in summer Bible camp.

The novel wastes no time introducing a robust cast of expendable blood sacks, from other campers to clueless teenage counsellors to Father Tony, the camp’s gleefully sadistic head counsellor. There are, of course, the usual rumours of fatal mishaps and accidents that have occurred in the past. Soon, campers and counsellors begin to disappear, and it becomes apparent that a murderer is on the loose. Before they know it, Martin and his new friends – Melissa, Courtney, and Joan – find themselves trapped in the middle of a real-life horror story.

With this reworking of the self-published 2010 novella Bible Camp Bloodbath, Comeau achieves a disarming balance between tragedy and dark comedy. The tension comes not from discovering who the killer is or why he’s cutting a bloody swath through the camp, but from the evident pleasure he takes in extinguishing each life – his gleeful knowledge that every time he interacts with a camper or counsellor, he is mere moments away from releasing his inner maniac. It’s as if each victim stabbed or bludgeoned to death with a sledgehammer is the punchline to a joke only the killer is in on.

Interspersed among the chapters are emails from Elizabeth describing life in Toronto and her experiences working on Blood Socket 2. (These emails to Martin include intertextual allusions to characters who appeared in Comeau’s earlier novel, One Bloody Thing After Another).

Elizabeth’s ongoing correspondence, though playful at first, reveals a fearfulness she works hard to hide beneath layers of flippancy and anecdotes. As the story moves forward, it becomes clear Elizabeth needs Martin’s presence in her life more than she lets on. While Martin experiences first love and friendship – and is simultaneously forced to fight for his survival – his mother becomes increasingly detached from reality. For his part, Martin attempts to use the knowledge of the horror genre his mother instilled in him to predict the killer’s behaviour in a manner vaguely reminiscent of Wes Craven’s Scream films.

Comeau uses brevity and detail to his advantage: the novel moves from one scene to another at a relentless pace. Locations and characters are sketched simply, while each killing is described with perverse attention to detail, from the sight of bright red blood juxtaposed with a counsellor’s blonde hair to the spray patterns of a ruptured carotid artery. The effect is powerful. When violence erupts, it stains the page.

The Summer Is Ended and We Are Not Yet Saved is a fast, occasionally terrifying read that manages to wear its blood-soaked heart on its sleeve. Comeau’s subtext-rich tale of a mother and son bond stretched to its limit walks a fine line between family values and all-out carnage, and does so with a spring in its step.