Scott Smith’s The Ruins isn’t one of those books that’s supposed to be funny—and, on the surface, it most certainly is not—but it’s so shocking, so horrifying, so painful that I couldn’t help myself: I laughed hysterically. Chalk it up to a defense mechanism, but this is a book that’s so unrelenting that even I, jaded ex-horror fan that I am, found myself gasping, slack-jawed, at the horror scenes. And what’s worse, there are no chapter breaks, so I raced through the book, alternately dreading and looking forward to what Smith had in store.

It’s a simple story that serves no purpose other than shock value: four college graduates—Eric, Jeff, Amy, and Stacy—and two strangers—Mathias and Pablo—all on vacation in Cancún, decide to search for Mathias’s brother, who’s followed a woman to a remote archeological dig around some fabled Mayan ruins. At its core, The Ruins is a survival story, with everything—time, the elements, even the plants—working against them, but Smith’s themes of friendship and trust force you to ask yourself how far you would go to survive. Giving up is easy, but what’s your breaking point? When does giving up become preferrable to survival?

Sure, the plot is pure pulp fiction garbage, but make no mistake: this book is great fun. Smith seems to be taking a masochistic joy in seeing how much pain, both physical and psychological, he can put his characters through. Unlike most horror novelists, however, Smith doesn’t spend much time describing what characters are feeling; he describes what they’re doing, so the novel plays like a movie, with Smith forcing you to watch as they try to extricate themselves from a situation that steadily goes from bad to worse. The Ruins is the perfect summer novel, neither complicated nor particularly original, and the Smith’s simple, unadorned writing style doesn’t draw attention to itself; it merely serves to tell the story in all its painful, horrifying glory.