Rebecca Owens is a young mortuary science graduate striving to overcome a troubled past defined by grief and
personal demons. Seeking a fresh start, she accepts a late-night apprenticeship at River Fields Mortuary under the eccentric and enigmatic mortician Raymond Delver. Driven by a desire to master her craft and prove her competence, Rebecca throws herself into the grueling, meticulous work of embalming the deceased during long, isolating night shifts. However, her ambition is soon tested when the boundary between the living and the dead violently shatters, plunging her into a waking nightmare.As a powerful winter storm traps Rebecca inside the mortuary, she discovers a terrifying truth. A malevolent demonic entity has infiltrated the facility and is binding itself to the corpses she is preparing. To survive the night, Rebecca must perform standard embalming procedures while simultaneously identifying which specific corpse possesses the demonic parasite. Her motivation shifts instantly from professional duty to raw survival. She must solve intricate occult puzzles, decipher disturbing historical clues hidden throughout the building, and confront deeply buried psychological trauma regarding her
estranged mother and her own father's tragic suicide.The entity preys on Rebecca’s deepest insecurities, guilt, and lingering grief, manifesting horrifying hallucinations that distort her reality and make it difficult to trust her own senses. She uncovers Raymond’s dark history with the supernatural and realizes that River Fields is a nexus for demonic activity, built on tragic sacrificial foundations. Each corpse she examines holds a fragmented piece of the puzzle, requiring her to perform specific rituals, burn sigils, and use ancient embalming chemicals to weaken the entity's grip.Throughout the harrowing night, Rebecca faces multiple terrifying encounters with the apparition, which constantly threatens to flay her soul and drag her into the abyss. Driven by an unwavering will to live and reclaim her agency, she perseveres through the gruesome tasks. In the climactic sequence, Rebecca correctly identifies the heavily possessed body and completes the final banishing ritual just as the demonic forces reach their peak. The entity is violently repelled into the nether realm, leaving the mortuary silent once more. Exhausted, traumatized, but ultimately victorious, Rebecca emerges from the furnace room as dawn breaks. Having faced her physical and psychological tormentors head-on, she finally achieves a sense of catharsis, ready to face her future with newfound resilience and strength.