Things go bump in the night, repeatedly, in Andy Muschietti's unsettling ghost story.
The Argentinean director masterfully sustains tension for the opening hour of Mama, teasing us with glimpses of the titular spectre, which runs amok in a frenetic finale.
But once Muschietti reveals his destructive apparition in her gnarled, twisted glory, and then proceeds to flesh out her convoluted back story, terror turns to incredulity.
Jessica Chastain, who is Oscar nominated for her lead performance in Zero Dark Thirty, lends gravitas to a potentially throwaway role as a surrogate mother who discovers her nurturing, parental instincts in the eye of a storm.
It's a solid performance, complimented by strong support from youngsters Megan Charpentier and Isabelle Nelisse as sisters who have been abandoned to a grim fate.
The film opens in 2008 as financial gloom pervades.
Businessman Jeffrey (Nikolaj Coster-Waldau) kills his partners and his wife, then takes his young children Victoria (Charpentier) and Lilly (Nelisse) for a drive into the mountains.
The car skids off the icy road and an injured Jeffrey seeks sanctuary with the girls in a rickety cabin.
"Daddy, there's a woman outside. She's not touching the floor," Victoria ominously informs her father, shortly before he comes to a sticky end.
Five years later, a search party locates the two girls, who have been living wild in the cabin under the watchful gaze of an invisible presence they refer to as Mama.
Jeffrey's twin brother Lucas (Coster-Waldau) is overjoyed that his nieces have been found, and he and rock guitarist girlfriend Annabel (Chastain) agree to provide a loving home to Victoria and Lilly.
Psychiatrist Dr Gerald Dreyfuss (Daniel Kash) expresses his desire to continue monitoring the children.
"I didn't get a chance to screw them up. They came that way," Annabel jokes to one of her band mates, unaware of the dangers posed by the dark spirit that watches over the urchins.
The fingerprints of executive producer Guillermo del Toro (The Devil's Backbone, Pan's Labyrinth) are all over Mama, which explores the power of otherworldly forces through innocent eyes.
Danger lurks in every dimly lit corner of Muschietti's film and he punctuates uncomfortable silences with edge-of-seat jolts. Once the nefarious spirit emerges from the shadows, the film falters, engineering a half-baked denouement that is both outlandish and peculiarly cathartic.