Nikaido Aya, a young lady in a box, is targeted by her father's hostile organization. She is still innocent and doesn't know much about sex, so she is a despicable thing to train Aya into a lewd meat slave and use her as a hostage for negotiations. She desperately resists, but she soon finds out that her anus is incredibly sensitive. She reacts to a number of overwhelming tortures and is remodeled into de M. She transforms from a neat and weak girl like an angel into a succubus.
