After a prank on their overbearing house mother goes wrong, a group of sorority sisters falls prey to an unknown assailant.

An opening prologue, set in 1961, plays out in an ethereal blue light. It’s night. Heavy rain pounds as we witness a woman giving birth in a house. The doctor arrives, nervous, and sets to work. Delivery complete, the doctor offers his condolences, and the woman wails in sorrow.

Fast forward to present day. The woman, Mrs. Slater, now serves as a sorority housemother. It’s the last day of school and she’s eager to see her charges leave. A Deep Red style children’s chorus fills the soundtrack as she looks at past class photos.

But a handful of girls opt to stay. Among them, spoiled hotheaded Vicki, virginal audience surrogate Katie, and fragile Morgan. Led by Vicki, they plan to host their end-of-year party at the house. Mrs. Slater won’t have it. When she catches Vicki in bed with a boy, she pops the waterbed mattress with her cane, leaving a half-naked Vicki humiliated.

Determined to get even, Vicki hatches a plan to play a good old sorority prank on Mrs. Slater.

Vicki’s plan proves too dangerous and leaves Mrs. Slater dead. Katie wants to call for help, but with the party set to begin, bends to Vicki’s pressure and joins the other sisters in hiding the body in the algae-laden swimming pool.

In a twist lifted from Diabolique, the body goes missing, leading the girls to suspect Mrs. Slater might still be alive.

This leads the girls to split up and search for her, which, of course, makes them easy pickings for the killer. The murders are gruesome but blink-and-you-miss-it-quick to mask the under-budgeted effects. We see a party goer speared in the neck by a cane, a sorority sister impaled through the chest, and another sister’s hand speared.

This last effect proffers an artificial hand that looks neither real nor female. Indeed, the most visceral kill plays out in shadow, where our minds impart the details the screen omits as the killer stabs a sister.

Morgan discovers Mrs. Slater’s body back in the house, setting up a Hitchcockian sequence where Vicki and others have to dispose of the body whilst the party is in full swing. They hide it in a dumpster, then wheel it to a van, only to bump into a cop car along the way.

Meanwhile, the killer continues his work, winnowing the sisters down to our final girl. More revelations as a theme emerges around covering up past sins. The script drags out the mystery of the killer’s identity, but the film proffers plenty of clues early about who it isn’t, rendering the biggest red herring obvious. When the big reveal comes, it underwhelms.

But I can forgive the muddled mystery. The film’s atmosphere compensates. The Pikesville, Maryland locales offer a refreshing change from the usual Southern California landscape, and the production charms with its verisimilitude. From the location sets, the local DC band (4 Out of 5 Doctors), to the pyramid of beer cans in the kitchen, to the posters on the walls, to one sister’s van’s wood-paneled interior, everything in the film feels lived-in and true.

I have a soft spot for these sort of early-80s, low-budget regional set horrors. Their atmosphere evokes a sense of nostalgia that obscures the suspect plotting and cheesy effects. For those of a certain age, this epitomizes the VHS-slasher.