‘Goodnight Mommy’ and other films.

Beginning with a gentle lullaby and ending with a tightly packed wallop, “Goodnight Mommy” is one viscerally chilling, seriously unsettling horror film.

When their recently single mother (Susanne Wuest) returns from the hospital to their isolated rural home, her face and head swathed in scary bandages following an “accident,” 9-year-old twin brothers Lukas and Elias (Lukas and Elias Schwarz) begin to have their suspicions. Outward appearance isn’t the only thing about this less-than-maternal woman that seems to have changed.

Determined to uncover the truth, the boys, no prize themselves, subject the woman to increasingly sadistic punishments to extract a confession.

Making an auspicious feature debut, co-directors Veronika Franz and Severin Fiala take a studied approach to the audacious subject matter that is more art house than grindhouse. They maintain an impressively composed visual command while adroitly ramping up the claustrophobic, menacingly atmospheric tension.

The drenched-in-dread results are so efficiently disturbing that the film — just announced as Austria’s official foreign-language Oscar submission — probably could have survived quite nicely without its shocker twist ending. Although plausible, it still feels gimmicky.

Even with its echoes of “The Bad Seed” and “Misery,” “Goodnight Mommy” unexpectedly hits a squirminducing nerve.

You’ll never want to be tucked in again.

“Goodnight Mommy.” MPAA rating: R for disturbing violent content, some nudity. Running time: 1 hour, 39 minutes. Playing: Nuart, West Los Angeles.