The series follows the incredibly lucky Futaba, who wins the grand prize in a lottery: the right to move in with her high school crush, Kousuke. Her wet dreams are about to come true, but she gets more than she bargained for when Kousuke's busty, sexually aggressive older sister, Ayaka, is part of the package. The story escalates from innocent romance into a full-blown vortex of debauchery. Ayaka quickly seduces the shy Futaba, teaching her the pleasures of girl-on-girl action with her talented tongue and fingers, making Futaba's pussy drip before Kousuke even gets a chance. This culminates in a series of relentless threesomes where Futaba becomes the siblings' shared fucktoy. Kousuke and Ayaka take turns plowing her tight holes, exploring every inch of her body. Futaba is double-penetrated, with Kousuke's thick cock ramming her cunt while Ayaka's fingers work her ass. The episodes are filled with scenes of her getting her face painted with cum, swallowing load after load, and screaming in ecstasy as both siblings bring her to explosive orgasms, leaving her a quivering, cum-soaked mess.