College student Shinsaburo becomes infatuated with Eri, his voluptuous married neighbor. He can't help but be captivated by her soft, full breasts and her round, plump big ass. Every day, he fantasizes about her while masturbating—until one day, she catches him in the act. Smirking, she says, "Were you jerking off thinking about your auntie? I'll give you a naughty punishment," and from that moment, his life changes completely. Day after day, he's immersed in pleasure, beginning a life that feels just like heaven.