In 1961, an unpopular boy named Harold leaves a Valentine's Day card at the home of Susan Jeremy. Susan and her friend David mock and crumple up the card, prompting an enraged Harold to break into the house, and kill David by hanging him from a hatstand.
Nineteen years later, Susan is divorced, has a daughter, and a new boyfriend named Jack. On Valentine's Day, Susan has Jack take her to a hospital to pick up test results, and on the way into the building, she is observed from a window by a man in surgical garb. The man strokes a photograph of a young Susan, and sabotages the elevator Susan boards in order to delay her while he kills the doctor who has her paperwork, which the murderer tampers with. A janitor finds the doctor's body, and has his face dunked into a sink full of acid by the killer.
While looking for the doctor, Susan coerces a friendly intern named Harry into getting her results, which Harry notices are abnormal, prompting him to bring them and Susan to Doctor Saxon. The peculiarities of Susan's paperwork (which the murderer further sabotages after killing a pair of laboratory workers) cause Doctors Saxon and Beam to order that she be detained for observation. Harry uncovers evidence suggesting that someone is pulling a "con job" on Susan, but he disappears after promising Susan he will straighten things out. Jack, who had fallen asleep in his car while waiting for Susan, enters the hospital to look for her, and is lured to an empty room, where he is decapitated. The killer places a box containing Jack's head in Susan's room, then replaces it with a cake (identical to one seen in the intro) when Susan goes in search of aid.
After Susan tells him about Harry's findings, Saxon goes to look over the copies of her paperwork in the archives, where he is murdered with an hatchet, an act witnessed by Susan. Susan's claims of there being a killer on the loose are disbelieved, and she is strapped to a gurney after being deemed delirious. The staff prepare to perform emergency surgery on Susan, but are killed in rapid succession by the murderer, who takes Susan to a vacant operating room. Susan pulls off the killer's mask to reveal he is Harry, who is really Harold. When Susan asks what he wants, Harold responds, "What I've always wanted. Your heart".
Before Harold can cut her open, Susan stabs him, and escapes. Susan is pursued to the roof by the wounded Harold, who she sets on fire, and sends plummeting onto the street below. The next day, Susan is released, and reunites with her daughter and ex-husband outside of the hospital.Barbi Benton as Susan Jeremy
Charles Lucia as Harold Rusk
Jon Van Ness as Jack
John Warner Williams as Doctor Dan Saxon
Den Surles as Doctor Beam
Gloria Jean Morrison as Nurse Dora Anders
Karen Smith as Nurse Kitty Crandle
Michael Frost as Ned
Jimmy Stathis as Tom Jeremy
Lanny Duncan as Hal
Marian Beeler as Mrs. Edelman
Elly Wold as Mrs. Fedrow
Jonathon Moore as Mrs. Parry
Gay Austin as Doctor A. Jacobs
Bill Errigo as The Janitor
Beverly Hart as Suzy
Ann Charlotte Lindgren as Nancy Johnson
Judith Baldwin as Desk Nurse
Tammy Simpson as Eva Jeremy
Elizabeth Hoy as Young Susan Jeremy
Michael Romano as David
Billy Jayne as Young Harold Rusk
Don Grenough as The Doctor
Jeremy Wheeler of AllMovie said that the film had "zero plot", but was still "a bloody fun time". An overall score of 2½ out of 5 was awarded by Adam Tyner of DVD Talk, who wrote, "X-Ray is kind of dumb and ridiculous, sometimes deliberately and other times not so much. Even though there's basically no gore to speak of, plenty of the red stuff still gets sloshed around. The hospital backdrop opens itself up for some gleefully twisted and frequently medical-themed kills. I really love the score, and my ears are pretty certain those are actual strings and not the usual early-'80s banks of synths. Taken as a pure horror flick, it's a misfire: zero successful scares and not all that much in the way of suspense. As '80s slasher junk food, something I'll never turn down, it's worth watching once. And, yeah, once; not sure this is something I'll ever give a second spin".
DVD Verdict's Tom Becker stated, "While it's fun for a while, X-Ray runs out of steam long before the ending, in which the killer is unmasked, to the surprise of probably no one. An extended final chase also goes on way too long. While the oddness here can be a bit charming—including a bizarre bit that has three elderly women looking for a doctor in a closed-off part of the hospital—it's a few rungs down from must-see, even for fans of '80s slasher sleaze". TV Guide succinctly concluded, "Unless you are a diehard [Barbi] Benton fan, this is a must to avoid".