Shortly before his fiancee broke off their engagement on Valentine’s Day 1986, Nigel Ralston began work on his horror spectacle Heart Attack. The film starts out innocently enough, treading a well-worn path that most horror fans would consider quaint, but, soon enough, it takes a turn into bizarre, twisted territory, which many film theorists believe was Ralston’s way of indicting his fiancee for, as he said, “ripping out his heart.”

The story opens with with an effective split-screen technique that shows two very different people whose lives will soon become inseparable. On the left side is Jim Thompson (played by Matt Stine, who has some great moments in the film), a down-to-earth, blue-collar guy. He wakes up next to his wife Miranda (Susan C. Lewis), has breakfast with his children and goes out to work on a tree house. There’s nothing unlikable about his character, which puts him in direct contrast with the character on the right side of the split-screen: Roger Perkins (played by the deliciously evil Rupert Blakenship, in a far too-short role).

Roger is a terrible person, to say the least. As the split-screen disappears, he’s watching a woman through the window of her apartment from across the street, a knife next to his leg. We know something terrible is about to happen, but we’re not prepared for it when it comes. In an expertly-filmed sequence, Roger breaks into the woman’s house, tortures her, and then murders her. A number of people believed the actress bore a striking resemblance to Ralston’s former fiancee, but he denies this allegation. “This scene was already filmed when she broke up with me,” he said.

As the murder plays out in another part of town, Jim is being a good father and husband, but something’s not right. His chest is bothering him. He shakes it off at first, but he’s obviously concerned. He continues on about his day as we switch back to Roger, who’s now on the run from the police. The split screen returns, and we see that Jim’s left arm is tingling now. He’s breathing heavier, just as Roger is, as he tries to escape the cops. Suddenly, as Jim clutches his chest and falls backward, his wife running towards him, an officer raises his gun and fires at Roger, who’s struck and goes to the ground. Both Jim and Roger lay on the ground as the camera climbs higher and the screen fades to black.

From this point, it’s not hard to figure out which path the movie takes. Obviously Jim needs a new heart, and Roger is executed, with his heart being a perfect replacement for Jim. However, as anyone who’s seen a body horror film can tell you, it’s not exactly perfect.

Soon after Jim returns home, he begins having strange dreams. He sees the girl that Roger murdered at the beginning of the film, but he sees it from his point-of-view, as if he’s the killer. Ralston didn’t seem concerned with the fact that it makes no sense for a man who gets a heart transplant to see things from the killer’s point-of-view, but it doesn’t matter, because the dream sequences are terrifying and well-executed.

Soon, Jim changes entirely, acting more and more like Roger, even speaking in gruffer tones like him. Stine seems to be having a blast in this role, and he said he worked with Blakenship to try really embodying both characters. He is, one could argue, successful, leaving behind the nice guy role from the beginning and turning into a downright awful person. Some of the dialogue is a little clunky, especially with his growling whisper, but he’s definitely having fun.

There are a few brutal murders, as you’d expect from this type of film, but what I was not expecting was the way the filmed turned into something completely different with only twenty minutes of running time remaining. If you don’t want to know, you might want to stop reading now, as there are spoilers from here on out.

So, Jim, possessed by the evil heart of Roger, is shot and killed by the police while he’s trying to murder his wife and daughter. One might assume that the credits were about to roll, but that would be very, very wrong. Ralston wanted to change things up a bit and he certainly did in the final scenes.

After Jim’s autopsy, the coroner is finalizing his report when he hears something from the other room. He goes to investigate and finds Jim’s heart missing. As he looks around perplexed, the somehow-sentient heart attacks the corner, scissoring through his chest with fangs in one of its ventricles. The coroner flops to the floor and we see his heart being pushed out of his chest. The murdering heart takes up residence inside the coroner, who soon stands to his feet and looks around, then takes a scalpel and leaves the morgue.

With this bizarre addition, the film takes on a whole new tone and becomes something that must be seen to be believed. Ralston was hailed by critics for his incredibly unique take on the genre, giving something to fans that they’d never seen before. Though there’s no real explanation for why the heart is sentient and why it has teeth, in the moment it doesn’t actually matter.

Ralston might want to consider thanking his fiancee from leaving him, or else Heart Attack would’ve never turned out exactly as it did, and that would’ve been the real tragedy.