a masochistic mother "yui" trained by a man called "master". one day, he orders her to offer her daughter "urara" as a slave. fearing she would be discarded if she refused, yui decides to offer her daughter. while urara is out, yui seduces her daughter's boyfriend and forces urara to watch their bondage sex. urara, inheriting her mother's masochistic blood, begins to feel sexual excitement and together they fall into the pit of bondage training.