After years of slapdash sequels, the Camp Miasma franchise is handed over to an enthusiastic young director for resurrection. But when she visits the original's star, a now-reclusive actress shrouded in mystery, the two women fall into a blood-soaked world of desire, fear, and delirium.

Academy Award® winner Jessica Chastain stars in a terrifying trip into the darkening world of a young girl, Bela, who forms a relationship with a disturbing entity in her home who looks uncannily like her own mother. "Other Mommy" proves to be more than a mere figment of the girl's imagination as she becomes a sinister, manipulative presence determined to tear apart Bela's family.