The pert perfection of Sarah Gadon — think Taylor Swift without the autotune — is given its first real test on the screen as something almost totally new in the movies — a “Mom Fatale” — in “The 9th Life of Louis Drax.” Alas, she’s no better here than she was in the woebegone “Indignation.”

“Drax” is an oddly remote and unaffecting (and unthrilling) thriller about a cruel and precocious nine year-old (Aiden Longworth of “Hector and the Search for Happiness”) whose mother is just catnip to the guys.

And that’s bad for the guys. Because young Louis, called “Lulu” by his parents, mistrusts men, thinking they only want “to sex” his mother and then hurt her. That leads to written , in nine-year-old scrawl, to one and all.

“Bad things will happen!”

But the bad things are already happening to Louis. He’s had an accident, at a picnic. He’s in a coma. It’s not, his doctor (Jamie Dornan) learns, the kid’s first dance with death. Read the title if you want to know how many preceded it.

Dr. Pascal (Dornan) tries to unravel the mystery of that day of the accident, and the kid’s past. There was a sympathetic shrink (Oliver Platt, terrific as always) treating him, puzzled by the child’s almost monstrous cruelty. He loves having pet hamsters, who all meet ugly ends.

There’s the boy’s boxer-with-a-temper dad (Aaron Paul), who’d have to be a suspect in any foul play. But not his mom. Oh no. Dr. Pascal is sure “You deserve better than this.”

“How do you know?”

“I can just TELL.”

The cop on the case (Molly Parker, so sarcastic you want to tear her head off) suspects one and all. Perhaps, like us, she’s seen any of the scads of TV medical dramas that have fed us remedial lessons in this sort of always-threatened/injured child cases.

Director Alexandre Aja has never come close to giving Hollywood a film as taut and frightening as his French breakout hit, “High Tension.” “Louis” has a creepily compelling young lead, but not much else. Paul isn’t scary enough to be the obvious suspect everyone else is sure he is.

There’s little suspense, and Dornan and Gadon both fail to register empathy, compassion, menace or fear.

The story shuffles between dark comedy and clumsy mystery, monster movie and psycho-drama, with no character or performance generating a whit of sympathy.

But in the movie’s big scene, Platt’s shrink is our guide into one of the cinema’s most informative trips into hypnosis. And that lets “9th Life” do something that few movies that fail this completely in the first two acts ever manage.

It finishes well.

MPAA Rating:R (for some disturbing images and brief strong language)

Cast: Aiden Longworth, Jamie Dornan, Sarah Gadon, Aaron Paul,
Credits: Directed by Alexandre Aja, script by Max Minghella, based on the Liz Jensen novel. A Summit release.

Running time: 1:30