In search of her missing sister, a nurse infiltrates a mysterious hospital on the night shift, only to find herself trapped in a deadly snare governed by four strict rules: no walking in the corridors at night, no approaching the operating room, and the even more ominous rule of "no basement."
The twin doctors are morally ambiguous; one secretly implants a tracking device and tests her at every turn, while the other, wrapped in bandages, invites her to form an alliance. The smell of disinfectant masks the filth of illegal surrogacy, and disobedient "spare parts" are imprisoned in a "dog kennel." Her sister's disappearance is closely linked to human trafficking and organ harvesting.
When the night shift bell rings, anesthetic needles, imposters, and deadly traps come at her in waves. She must fight tooth and nail in the gap between desire and conspiracy to tear away the hospital's veil of evil and rescue her sister and countless other victims.
