There’s a common thread in Joe Hill’s works: one way or another, they all break your heart. Needless to say, The Fireman continues this gut-wrenching tradition.

A colossal read at 768 pages, the post-apocalyptic opus opens at the beginning of the end:

Harper Grayson had seen lots of people burn on TV, everyone had, but the first person she saw burn for real was in the playground behind the school.

The book doesn’t pull its punches. Even the prologue comes quick and sharp, with a feint and nasty uppercut. First, we’re introduced to our protagonist, Harper, a school nurse with some endearing idiosyncrasies, including a Mary Poppins lunchbox and a penchant for happy musicals. Then, while Harper fusses over a first-grader, The Fireman brings in the next act. A pathogen is blazing across the country. Its scientific name is Draco Incendia Trichophyton, but people just call it Dragonscale.

A man shambles onto school property. He’s dressed plainly, face shadowed by a grimy baseball cap. Gouts of smoke pour from his sleeves. As Harper watches, he sags to his knees and suddenly begins to burn. While his death is not explicitly described, the repercussions are vividly illustrated. The school erupts into hysterics. Teachers are rushing to placate screaming children, all the while wrestling with their own terror. Despite their best efforts, some succumb to tears. Months later, a teacher named Miss Pym burns to death in a bathtub with the shower still running before being eaten by starved corgis.

Miss Pym’s demise is emblematic of The Fireman’s narrative tone. It’s horrifically grim in places and full of human desperation, but also darkly comical. I mean, who gets eaten by Pembroke corgis? With that mood set, The Fireman continues on, following Harper out of school and back home, where she sits and trembles and talks with her husband, Jakob. The domestic interlude doesn’t last. Soon, they’re watching as people fling themselves from Seattle’s burning Space Needle.

And somehow, things are still getting worse. Cut to Harper working in an overcrowded and undersupplied hospital, stowing bodies into body bags, “their blackened, shriveled tissues still warm to the touch, still fuming.” Hill does a stellar job with the atmosphere here. We find out that Harper isn’t just dealing with corpses; she’s packing away dead children who have burnt to death with their arms around one another, who have “fused into a single creature, a tangled cat’s cradle of charred bones.”

His description of Harper’s personal condition is no less gruesome:

She hadn’t been home in five days and spent 18 hours of 24 in a full-body rubber suit that had been designed to repel Ebola. The gloves were so tight she had to lube her hands up with petroleum jelly to get them on. She stank like a prophylactic. Every time she inhaled her own fragrance of rubber and K-Y, she thought of awkward college encounters in the dorms.

It’s no wonder that the hospital responds poorly when the eponymous fireman arrives with a boy in his arms, shouting for medical attention. A conflagration ensues. Threats are made and lines in the sand are drawn. The fireman’s character is established: compassionate, English, utterly incongruous with societal expectations.

Now, the main pieces are in place—along with our first big mystery. Who is this fireman? And why was he conspicuously gnawing at his glove in the hospital? Moving at an impressively breakneck speed, The Fireman doesn’t answer that question immediately, instead it takes us deeper into the cataclysm, smearing us with death and ashes and loss, the Dragonscale hovering like a specter.

Hill makes it clear that an epidemic isn’t just a distant menace; it's something that infects microcosms of daily life. Through Harper’s eyes, we witness how adversity can bring out the best and worst in our species. On one end of the spectrum, we have Renee Gilmonton, a defiantly good-natured nurse who retaliates against the apocalypse by being nice, organizing reading sessions, and rushing into danger for complete strangers. On the other, we have Harper’s husband, Jakob.

When Harper reveals that she is contaminated with the Dragonscale fungi, he completely loses it, blaming Harper for everything that has happened: her unexpected pregnancy, her illness, even her unwillingness to fulfill their pledge to commit double-suicide.

There’s something delightfully vicious about the way Hill portrays Jakob’s villainy, but it’s also a symptom of how disinterested Hill seems in humanizing his antagonists. None of the villains are remotely complex or ambiguous. The Marlboro Man, for example, is a screeching doomsayer, spitting misogyny with cartoonish enthusiasm. I can only think of one evildoer in the book who surprised me—and even then, I had my suspicions about the character.

The novel shines brightest when Harper takes the lead, joining a community of fugitives who are infected with Dragonscale. Present are all the necessary parts for a Lord of the Flies-esque romp: violence, treachery, uncontained lusts, power struggles, even everyone’s favorite foible, neo-religious fanaticism. Hill gleefully mixes these elements to impressive effect, occasionally imbuing them with pathos, occasionally delighting us with scenes of tragicomic gore.

But The Fireman isn’t The Walking Dead, to put it into perspective. For every atrocity, Hill introduces a small and precious moment of humanity. People persist here. They survive. Adjust. Sisters argue about stolen nail polish. A nurse reads Watership Down with convicts. A boy stalks a cat through the apocalyptic wilderness—not to devour the feline, but to domesticate it. And on Thanksgiving, the community rejoices in the miracle of hot chocolate and marshmallows.

Human relationships obviously take center stage. Like any self-respecting post-apocalyptic novel, The Fireman features slow-burning romances, the most prominent being the one that grows between Harper and the titular fireman character, John Rockwood. Equally enthralling are the platonic connections. It’s nice to see men and women interacting without the temptation of sex or women being friends without any competition or jealousy. This isn’t exactly a new thing any more, and the push for diversity in the genre has done enormous good. But it’s still incredibly nice to see.

Rife with pop-culture references and nods toward his father’s work, The Fireman spends about two-thirds of its existence as a science fiction thriller. In the final act, however, things take a fantastical turn. Early on, Hill states that almost all of the individual traits of the Dragonscale exist within the natural world, and the resulting pseudo-science comes across as quite believable. But come the last third? It all goes out the window. I won’t spoil how it happens, but if you’re looking to enjoy The Fireman, I suggest keeping that in mind. Otherwise, you will be miffed. I certainly was.

Overall, however, The Fireman is beautiful and aching and striking, a poignant exploration of human relationships and an ode to the simple things. I would have liked a better ending, something that didn’t quite wrap up so tidily. But fiction isn’t reality, and when you’re dealing with world-annihilating fungi, what’s wrong with having a spoonful of sugar to help the medicine go down?

The Fireman comes out today, May 17, in the US. Residents of the United Kingdom will have to wait until June 7.