Margaret lives with a rare autoimmune condition that has destroyed her life, leaving her isolated. It has no cure, but she's making do as best she can-until she's offered a fully paid-for spot in an experimental medical trial at Graceview Memorial.

The conditions are simple, if grueling: she will live at the hospital as a full-time patient, subjecting herself to the near-total destruction of her immune system and its subsequent regeneration. The trial will essentially kill most of, but not all of her. But as the treatment progresses and her body begins to fail, she stumbles upon something sinister living and spreading within the hospital.

Unsure of what's real and what is just medication-induced delusion, Margaret struggles to find a way out as her body and mind succumb further to the darkness lurking throughout Graceview's halls.