And again, Barbara Hershey plays the scary mom. This time she’s not haranguing her beset daughter to eat pink birthday cake. This time she’s haranguing her beset son to recover repressed memories.

In Insidious, that son is Josh (Patrick Wilson), a less than happy schoolteacher married to Renai (Rose Byrne) and father to three young children. He’s convinced the wife to move to a new house, in search of a new start following an unidentified trouble. She’s a songwriter, or more precisely, finally getting back to writing after birthing babies. And yes, she will be punished for spending time at the piano while the baby’s upstairs alone—or, er, not so alone.

No surprise, the new house is soon revealed to be something like a cross between that place on the Indian burial ground and the other one in Amityville and probably the one plagued by Paranormal Activity too. The first and most obvious clue comes when young Dalton (Ty Simpkins) checks out a creaky attic and comes out in a coma. Doctors can’t explain it (“There’s no brain trauma!”) and his parents are horrified, for a minute anyway: the film jumps ahead a few months so that Dalton comes home from the hospital to lay pale and pathetic in his bedroom.

The creepiness in James Wan’s film has mostly to do with pace. A prelude to the whole business has informed you that a sinister face-in-the-window is laying claim to little boys’ souls, but Renai and Josh take an interminably long time to sort out what you anticipate. The camera tracks slowly behind her as she makes her way through various hallways and investigates odious noises.

It spends less time watching Josh fume and evade, heading off to class rather than helping his wife deal with their infant, their comatose child or their other son, Foster (Andrew Astor). He tells his mom that he’s scared of Dalton: “I don’t like it when he walks around at night.” She doesn’t quite hear that right, but struggles with her own encounters, shadows skittering across the floor or hiding in closets, laughing at her and wearing old paperboy-style clothes (because, apparently, olden days costumes are scary). At last Renai finds a sign of intrusion she can’t live with—while Josh is staying late at school—and so she rages, cries, and insists they leave this terrible place.

Too late. Just days later, when they’re unpacking boxes again, it’s obvious to all but the willfully ignorant Josh that they’ve left none of their troubles behind. The monsters they’re dealing with are so… insidious that they’ve hitched a ride with the family. If Josh is slow, and frankly, rather resistant, to grasp the truth, his mom, Lorraine, finally makes him. Here we see the motive for Hershey’s casting: she’s not just any reasonably worried grandmother, but a mom with a terrible secret. This won’t be a surprise to anyone—except, rather vividly, her son.

Lorraine’s secret involves her longtime friendship with a psychic, Elise (Lin Shaye), who informs Josh and Renai—as you’ve seen in the trailers for Insidious—that it’s not their houses that are haunted, but rather, their son. This haunting sounds a lot like possession, but there’s no exorcist in sight, only this pert lady and her pair of nerdy employees, Tucker (Angus Sampson) and Specs (screenwriter James Whannell). Their quick survey of the situation with homemade equipment produces a dire prognosis. Only after Josh is advised that Dalton is lost in “astral projections,” besieged by spirits from a place Elise calls “the Further,” does he notice his son’s own pleas for help—startlingly violent black and red crayon drawings. Looking over his shoulder as he peruses these messages, you can’t help but wonder at his surprise. How long have these pictures been tacked to Dalton’s bedroom wall, anyway?

Elise looks about to speed up the action when she arrives ready for a séance-y sort of effort. She dons a contraption that resembles a gas mask in order to communicate with the boy and any monsters hanging about, monsters who know her, as they call her a “bitch” and other mean names. “Leave the vessel,” she tells the bad spirits. Before you can say “Father Merrin,” furniture is crashing and Elise is pitching too and fro and Dalton’s parents are looking horrified indeed.

Elise in the mask is a sight to be savored, as the scene insists. Here and elsewhere, you’re reminded why Wan and Whannel have a reputation for conjuring effectively quirky horrors. Even if story and sense are not their strong suits, they know how to imagine an utterly eerie image. The camera pans the faces gathered in eight-year-old Dalton’s room, adults uncomfortable and unable to comprehend the childhood fears they’ve left behind. As Elise begins to whisper communications from beyond, Specs scribbling her words and also speaking them furiously for his rapt audience, you’re reminded that being a child can be very, very scary. Adults like to forget that.