A horror film with Oscar-winning actress Helen Mirren, the ever-serviceable Jason Clarke and Sarah Snook, plus the deliciously spooky Winchester Mystery House, a real Bay-area Gothic mansion with creaky floorboards and inherently creepy antiques—what could go wrong? Well, in the case of “Winchester,” (Rated PG-13) just about everything.

In “Winchester,” screen legend Mirren portrays the real-life Sarah Winchester, an eccentric heiress who translated her late husband’s Winchester Rifle Company fortunate into the building of a San Jose mansion (which remains a popular tourist attraction for haunted house lovers to this day) in the early 1900s.

There, she houses her niece Marion (Snook), Marion’s young son Henry and, if you were to ask Winchester, several ghosts of people who were shot and killed by Winchester rifles. These hauntings compel her to hire a team of construction workers to renovate and add new rooms to the mansion on a 24/7 basis.

Winchester’s conviction that these spirits live in her home, and must be accommodated through endless renovations, prompts the powers that be at the Winchester Company to enlist the services of Dr. Eric Prince (Clarke). Prince, a widower who has taken to assuaging his grief with laudanum and philandering, must conduct a full psychic evaluation of Winchester, an evaluation that (for reasons the script is too lazy to explain) will require him to stay at the mansion for a full week.

As Prince commences his evaluation, “Winchester” seems poised for a thrilling ride. The Mystery House, complete with unexpected interior walls that double as windows and maze-like staircases, is the perfect playground for terror to unfold (the film’s high production value is one of its few strengths).

Unfortunately, “Winchester” proceeds to shoot itself in the proverbial foot in a myriad of ultimately insurmountable ways. Wherever there’s an ill-advised creative decision to make, the directing team of identical twin brothers Michael and Peter Spierig finds it.

The Spierig brothers only have themselves to blame for the movie’s most glaring problem—it’s utterly insipid script, which they penned with Tom Vaughan, and which plays out like a first draft slapped together over the weekend. All the tension built in the film’s initial stages gives way to an exhausting parade of jump-scares that becomes so repetitive, you almost wonder if the film is being played on a scratched DVD.

Just as egregious as its narrative execution is “Winchester’s” confoundingly misguided choices in regards to character development. Instead of taking the obvious route of allowing the always-sensational Mirren to lend her talents to the real-life personality of her character, the script renders Winchester a throwaway, shoving her into the corner in favor of exploring the fictional Prince in a convoluted plot thread involving his late wife that doesn’t add up, not that we’d care even if it did.

Frankly, “doesn’t make sense and doesn’t matter” is the perfect slogan for the movie as a whole The third act’s revelation of the loophole that will allow Prince and Winchester to exorcise the demons from her mansion elicits nothing more from us than a “sure, why not?” You’ll find yourself rooting for Prince and Winchester to succeed, but only so that you can move on with your day and get the bad taste of this total waste of time out of your mouth.

To the credit of both Mirren and Clarke, it never feels like either is slumming; on the contrary, both deliver restrained performances, without giving into the type of macabre mugging so often characteristic of  horror films that mail it in. Instead, we actually feel bad for Mirren and Clarke, who, much like the characters they portray, are trapped within a nightmare.

And to make matters worse, the characters surrounding Mirren’s Winchester and Clarke’s Prince are tremendously undercooked and devoid of any distinguishable personality. Everyone we encounter in the Winchester Mystery House is either a ghost, or might as well be. Indeed, “Winchester” serves as further proof that no one, not even the great Helen Mirren, can save a bad script.

At the conclusion of “Winchester,” immediately following information about 1906 San Francisco, which has almost nothing to do with anything we just watched, we are shown a faded black-and-white photo of the real Sarah Winchester, looking right into the camera and curbing a smile—almost as if she’s taunting us about the squandered opportunity to depict her intriguing true story with the treatment it deserves. What a shame that Winchester, who so famously funded around the clock construction and demolition on her mansion, couldn’t make the same arrangements needed to reconstruct this film.