In a small-town high school, Anita "Needy" Lesnicki and Jennifer Check are best friends, though their social statuses are quite different: Needy is an average student living a quiet life, while Jennifer is a popular cheerleader. Their lives take a dark turn after they decide to attend a local bar to see an indie band perform. The night erupts in chaos when a fire breaks out, leaving several dead. In the aftermath, Jennifer, dazed and bloodied, encounters the band's lead singer, who convinces her to leave with them.

Traumatized by the night's events, Needy grows increasingly concerned when Jennifer returns with a disturbing change in her demeanor and an insatiable hunger. A string of gruesome deaths begins to plague the town, and Needy discovers that Jennifer has become a succubus, a demon that preys on human flesh, particularly targeting teenage boys. As Needy uncovers the horrifying truth behind Jennifer's transformation, she finds herself in a desperate fight to save her friend and stop the bloodshed, while coming to grips with the dark secret the band harbors.