Lisa Templeton begins a new job as a cleaner at High Hopes Hospital, a mental institution in Amityville, Long Island. Initially delighted to get the job, Lisa soon realises that all is not as it seems. Intimidated by staff and the psychotic ramblings of the patients, she is further unnerved by apparent supernatural occurrences on the night shift. To preserve her sanity, Lisa must uncover the mysterious history of the institution and its inmates. But the truth is far more terrifying than she could ever imagine.