Directed by James Wan. Starring Patrick Wilson, Rose Byrne, Ty Simpkins, Lin Shaye, Leigh Whannell, Barbara Hershey 16 cert, gen release, 102 min

“A PARASITE! She befriended your Astro body and lured you into the Further.” Yeah, yeah, exorcist lady, we know how possession movies work.

Director James Wan and screenwriter Leigh Whannell, the wunderkinds behind Saw, are also up to speed.

If Jigsaw was a moral, platform-gamer-friendly riposte of Freddy Krueger, then Insidiousis Poltergeistin a fairground house of mirrors; the Tobe Hooper film, you may recall, was not short on carnival in the first place.

In keeping with its handle, Insidiousis a sneaky, shifting thing. Eagle-eyed viewers will, during the garish opening credits, note Paranormal Activity's Oren Peli's involvement as a producer. Wan's film opens as a probable franchise stepsister to the Israeli director's breakthrough hit. Harried married couple Josh and Renai (Patrick Wilson and Rose Byrne) have just moved into a Creaky Old House with their two young sons and a baby when things start to go bump in the night. You know how it is: chairs move of their own accord, books fly off shelves, Barbara Hershey pops up as Josh's disconcerting mother.

Before you can say “Indian burial ground”, the couple’s young son Dalton has fallen into an unexplained coma and noisy ghosts are using the bedrooms as thoroughfares. The family are in agreement: it’s time to call in an agreeably wacky gang of spiritualists to kick some spectral ass.

Director Wan provides a masterclass in old-school, dark-house grammar. The camera snakes about with malicious intent. The soundtrack plays out as a concrete opera musique.

But at the moment when the film must face down its demons, all bets are off. Whannell drily channels Ghostbusters' Bill Murray as a visiting geek-boy paranormalist; Lin Shaye does a muted Zelda Rubinstein; the third act lets fly with full-blown grotesquerie.

Most film-makers shy away from exposing their monsters; Wan and Whannell bring them on in chorus lines. On the ceiling there’s a clawed demon; on the floor, there’s a corseted Tim Burton heroine that may have been attacked by Salvador Dali with a blowtorch.

At heart, it's a ghost train in the style of Wan's underrated Dead Silence. It keeps us amused because it abides by its own batty rules about astral projection and because Wilson and Byrne keep up a delicate domestic drama when the dead folks come a-calling.