Blood.

Jess, a newly separated mother and nurse, moves into her old family farmhouse with Tyler, her teenage daughter, and Owen, her eight-year-old son. One night, the family dog senses something in the woods and runs off to find it. He returns a couple of days later and attacks Owen, savagely biting him before Jess is able to intervene. Owen is rushed to the hospital. His condition worsens, and no one can figure out why... until Jess discovers a disturbing cure...