When college undergrad Bethany puts on a silver necklace she found while hiking in the woods, she thinks it's just a cool piece of jewelry depicting a serpent. But she wakes up in the middle of the night to find a tiny snake in her hair-one she can't get out. She cuts it free and it slithers away. A second snake appears, followed by many more, and she realizes that her hair is actually transforming into serpents. When she cuts them away, not only does she have deadly snakes slithering around the house, but more snakes spring up from her scalp to replace them. Things get weirder when her gaze turns her parents into stone. But it's not a quick transformation. It's a slow, body horror nightmare like kidney stones taking over their bodies from the inside.

Bethany hides away, trying to figure out what to do. She's growing fangs and her body is developing scales. Is she going to have to rip out of her own eyes to spare people from her gaze? People just won't stop coming to the house, including a pair of home intruders, for whom things turn out very badly. Bethany is amassing quite the statue collection. Then she learns that neighbors and classmates are being discovered in stone form. Because there's a full Medusa lurking around town, and she wants her medallion back, even if the only way to get it is to take Bethany's head with her.