★ ½

The Insidious franchise has introduced some interesting characters over the course of its eight-year, four-film run, both ghostly and otherwise. Since her debut in 2010’s Insidious, Elise Rainier (Lin Shaye), medium extraordinaire and cleanser of specter-infested dwellings, has ranked among the best of them. The fourth offering of the horror series, Insidious: The Last Key, promises to delve into Rainier’s tragic backstory, examining the lengths she’ll go to in order to banish the demons of her past (both literally and figuratively).

The movie opens with a horrifying flashback to Rainier’s childhood home. Her family lives near a large prison, where her abusive father works as a corrections officer. When he’s not at work or falling asleep in his glass of whiskey, he’s trying to beat Elise’s clairvoyance out of her. She communicates with spirits anyway, including those of a young boy trapped in her room and the ghost of a man just sent to the electric chair for murder. As if all of that weren’t traumatic enough, she ends up unwittingly unleashing a terrifying demon by unlocking a mysterious door in her basement, which ends up killing her beloved mother.

Fast-forward to 2010: Rainer and her found-family sidekicks Tucker (Angus Sampson) and Specs (Leigh Whannell) are running their own ghost-busting business out of her home. Things take a turn for the extra bizarre, though, when the crew answer a distress call from a man living in Rainier’s childhood home. Not only must she deal with the entities plaguing the resident of the home—both dead and alive—she must also face the ghosts of her past in the form of her estranged brother Christian (Bruce Davison) and his two daughters (Caitlin Gerard and Spencer Locke).

Conceptually, the film is quite interesting; despite its heavy-handed symbolism of literally exorcising one’s personal demons, the skeleton of Rainier’s backstory has much to offer, and is laden with themes of family, heredity, breaking the cycle of abuse, and acceptance. Unfortunately, it is just that: The barest bones of a story, with so little substance that not even the least demanding fans of the franchise will feel satisfied. Additionally, the demon, whose name is apparently Keyface (inexplicably—it has keys for fingers, not on its face), is never fleshed out. That’s disappointing, since the lore behind the monsters is an area where producer James Wan and screenwriter Leigh Whannell usually excel. Plus, the demonic entity looks about as snort-worthy as its name sounds.

Though Shaye acts her heart out as fan favorite Rainier, her stellar performance alone isn’t enough to carry this movie. It just feels tired, turning to cheap, predictable jump scares for the occasional audience freak-out and relying on enough unoriginal, heteronormative comic relief to make your eyes roll out of your head and onto the floor. Even the franchise’s usually fantastically creepy netherworld, the Further, looks dull and half-baked this time around. The good news is that at least the film is fairly short, clocking in at just over an hour and 40 minutes.

Wan is clearly devoting most of his creative energies to The Conjuring franchise these days, as Insidious: The Last Key feels like it’s scraping the bottom of the Further for the last few box-office sales. Hopefully this exhausted series can now be laid to rest, and Wan can just focus on making quality horror.