In a quiet rural area, a journalist named Ted returns home after a trip to visit his sister, burdened by a dark and disturbing secret. Ted is the only one who knows that his brother, a former soldier named Mac, has been bitten by a mysterious creature that has unleashed his wild and bloodthirsty side. However, the real dangers do not only lurk in the darkness; Ted's family lives in the neighboring house, and their dog is the first to notice that something is wrong.
As the nights grow increasingly sinister, Mac's transformation intensifies, turning him into a being driven by his most primitive instincts. What began as a simple visit evolves into a bitter fight for survival when his sister and her son become trapped in the chaos that Mac has unleashed. In his desperate quest to contain the violence of the supernatural being that inhabits his brother, Ted faces not only physical horror but also a painful family connection that threatens to unravel.
The tension escalates when Mac launches his attack against the innocent, and each full moon brings with it the promise of death. In an exhilarating confrontation between the beast and familial ties, the lines between humanity and savagery blur, testing the limits of brotherly love and sacrifice.