Sayaka, a high-achieving student from a wealthy family, faces ruin when her parents vanish due to massive debts, forcing her into a part-time job at a shady family restaurant. The sleazy boss Kuroki blackmails her into midnight "special services," where she becomes a sexual menu item for depraved customers, enduring intense training and humiliation. As her younger sister Moemi grows suspicious and stumbles into the web of exploitation, the sisters descend into a cycle of gangbangs, mind break, and coerced pleasure at the restaurant.