I Know What You Did Last Summer lost its empathy in its move to the big screen

It’s a small thing, really: a period instead of an exclamation point. The difference between a statement of fact and an accusation. “I know what you did last summer.” rendered in simple block print. “I know what you did last summer!” written in a similar hand, the manic edge of desperation bleeding through the paper. A threat, no matter which way you look at it, diverging only in the kind of dread it calls up from somewhere deep in your gut.

In Lois Duncan’s 1973 young adult thriller novel I Know What You Did Last Summer, protagonist Julie James receives an anonymous letter containing that single sentence punctuated by a period. In director Jim Gillespie’s 1997 film adaptation of the same name, Julie receives a near-identical letter; the only change is that the sentence is punctuated by an exclamation point instead. In the novel, the message’s ambiguity causes nervous bile to rise in the back of your throat, the kind you can’t seem to swallow no matter how hard you try. Who is this person, and what are they going to do with this information? In the film, it’s a death-drop plummet with no floor: Whoever this is, they’re coming for me.

“Without my consciously intending to insert it, all my YA novels seem to contain an ‘unstated, read-between-the-lines message’ about the importance of taking responsibility for our own actions,” Duncan said in a 2002 interview with Absolute Write. She was responding to a question about another of her novels, Killing Mr. Griffin, but she’s correct about the theme applying more broadly to her work (which includes some 27 works of YA fiction, plus nearly two dozen nonfiction, poetry, and children’s books). In her hands, I Know What You Did Last Summer is a cautionary tale, a deeply empathetic portrait of a group of teenagers who make a horrifically bad choice and eventually own up to it. Julie James, a high-school junior on summer break, is coming home from a night of partying with her friends, seniors Ray Bronson (Julie’s boyfriend at the time), Helen Rivers, and Helen’s boyfriend Barry Cox. They’ve all been drinking and smoking pot. Barry’s driving, too fast, as he always does, down a mountain road somewhere in the American Southwest. And then there’s a bicycle caught in the headlights, just a split-second view of a young boy before the impact and the crunch and the jolt as the car drives over his body, and just keeps going. Ray calls emergency services from a pay phone a mile down the road, but it’s too late. Ten-year-old Daniel Gregg is dead by the time the ambulance reaches the hospital.

After the crash, Julie wants to stop and confess, but Barry refuses, saying that they’ll call for help, but sticking around won’t do anyone any good. It’ll just ruin all their lives, and for what? He’s got far too much to lose, and taking responsibility won’t change what happened. Ray initially sides with Julie, but when it comes down to a vote, Ray flips, staying loyal to Barry, his best friend. Helen sides with her boyfriend. It’s three against one; they’re going to cover up the crime. Ray and Barry hammer the dent out of the bumper, repaint the car, and sell it to a farmer. They don’t talk about what happened after that. 

I Know What You Did Last Summer is written from a third-person point of view with perspectives shifting between characters in each chapter. We spend the most time with Julie, but we get to see what Ray, Helen, Barry, and even Julie’s mom think about what happened, too. Julie’s overwhelming guilt manifests as a desire to better herself—to buckle down, focus on her studies, and get into a prestigious East Coast university, which she does. The novel, in fact, opens with that small moment of joy, followed immediately by the destabilization of the anonymous letter. Julie’s mom is puzzled by her daughter’s change in personality, but it seems to be for the better, so she pushes her concerns aside. Ray cuts and runs, heading for the California coast to work odd jobs while remaining only sporadically in touch. Helen doesn’t think much about that night at all, focusing instead on her surprisingly good life as a local news correspondent. And Barry’s still deeply in denial, lying to himself and everyone around him about what happened back then and what’s happening now. The letter is a prank, he says. How can they even be sure it’s referring to the crash? It could be about anything, and they’re probably getting worked up over nothing.

Duncan’s Killing Mr. Griffin deals with similar themes to I Know What You Did Last Summer. A group of students kidnap an ornery teacher who grades them harshly; he dies in the middle of the ordeal, and, spurred by the group’s de facto leader, Mark, they cover up the crime. In that same interview with Absolute Write, Duncan explained the impetus for the novel: “I started thinking about charismatic psychopaths like Charles Manson and wondering what they were like as teenagers? They didn’t just spring full-blown from oyster shells—they had to hone the ‘people skills’ that allowed them to become so manipulative as adults. Kids like that are growing up within our school systems and can exert tremendous control over their fellow students. I consider Griffin a cautionary tale about the danger of peer pressure.” 

Barry starts out in a similar vein as Mark, coaxing his friends to keep quiet even as the threats begin to mount. An anonymous phone call, in which the caller claims to have photos of the crash, draws Barry out to an empty field, where someone shoots him and leaves him for dead. He survives, but tells his friends it was a robbery and lies to them about the mysterious call. Unlike Mark in Mr. Griffin, though, Barry is capable of change. When the attacker later tries to kill his friends, he decides to end the charade and confess to his crime. Barry’s not a sociopath—he’s just stubborn and dangerously selfish. Duncan’s book argues that people are inherently good, and that there may be no forgiveness or absolution from the ways in which we hurt each other, but there is still value in trying to be better today than you were yesterday. From the perspective of an adult, I Know What You Did Last Summer is less a thriller and more a painfully trite lesson in morality, but for its intended audience of young teens, the message resonates powerfully.

Given the book’s ultimate message, it’s not surprising that Duncan hated Gillespie’s big-screen adaptation. Screenwriter Kevin Williamson stripped the plot down to its bones and constructed a whole new body around it, one that diverged wildly from the point of Duncan’s novel. In Williamson’s version, there is no redemption, no ultimate acknowledgment of the group’s crime. Instead, the four teenagers, played by Jennifer Love Hewitt (Julie James), Freddie Prinze Jr. (Ray Bronson), Sarah Michelle Gellar (now Helen Shivers rather than Helen Rivers, in one of the more egregious and unnecessary changes from the book), and Ryan Phillippe (Barry Cox) find absolution in a technicality: they didn’t actually kill the person they hit—this time a full-grown adult named Ben Willis (Muse Watson), who was on his way back from murdering another kid—so they have nothing to feel bad about. In fact, Ben’s the bad guy in this situation, not them. He’s the one who ran around trying to kill them (and succeeding, in the case of Helen and Barry) on purpose, but they just hit him by accident. (And then purposefully dumped him in the ocean while he was still alive, but that’s just a pesky little detail.) Clearly, this is all Ben’s fault. That’s why Julie and Ray, the two survivors and the two who pushed hardest for turning themselves in, ultimately tell the police they have no idea why Ben would want to kill them, continuing to cover up their crime even when they had a perfect opportunity to confess.

It must have felt like a slap in the face to Duncan, who was ultimately trying to impart an important lesson to young adults with her book. The movie version of I Know What You Did Last Summer is an R-rated slasher flick with a paper-thin and often nonsensical plot that focuses entirely on twists and reveals. As an adaptation of Duncan’s book, it’s sacrilege. Unfortunately for Duncan, though, as a slasher movie, I Know What You Did Last Summer is a pretty good time.

In part, the film works so well because it doesn’t feel like Williamson fundamentally misread Duncan’s text. He clearly read and understood it; he just had a different vision for the story. Williamson’s take reads like an alternate-reality version of Duncan’s: What if, instead of a character drama about how people can change and grow told through thriller elements, the characters don’t matter and all the drama and plot come solely from the cheap thrills of the central mystery? What if, instead of a period, it was an exclamation point?

Start with: The movie. If you read the book first, you’ll experience a wide range of mostly negative emotions about the movie’s massive changes. The movie is inherently less than the book—less deep, less grounded, less realistic. Watch the movie first, though, and the book will offer you more details on pretty much every aspect of the film. It’s more satisfying to go from less to more than more to less.