Suika is the eldest daughter of the family. Instead of "papa-katsu" (sugar dating), she engages in "chichi-katsu" (a pun involving breasts), easily luring older men for pocket money... Or so she thought. The man who appeared, introducing himself as Masuo, was someone who knew everything about Suika's breasts! Experiencing the pleasure of tit-fucking for the first time, Suika's body and mind begin to fall into depravity...