Charley Hart, the unwitting matriarch, returns home to find her stepson, Alexander Vega, buried between his stepsister's, Lilith Grace's, thighs. Instead of outrage, she feels an unfamiliar stirring. As Alex's tongue explores Lilith's tight, teenage slit, Charley can't help but notice the growing tent in her son's pants. She watches, hidden, as they graduate from oral pleasures to intense, doggystyle fucking, their moans echoing through the house. When Alex pulls out, painting Lilith's back with his hot cum, Charley steps in, licking the evidence from her daughter's skin, marking the beginning of their twisted, familial threesome.