Warning: spoilers

When Sado Tarou was in his third year at junior high school, a really cute girl he didn’t even know suddenly came into his classroom and slapped him, while crying “You should die!” This fateful event awoke his latent masochism… and before he knew it, he was on his knees, asking the mysterious girl to hit him, to insult him, to humiliate him. Ever since, he was labeled as a pervert, and shunned by almost everyone.

In the present, Tarou awakes to find his sister, Sado Shizuka, sleeping in his bed. A 19-year-old university student, is also a brocon… who is always fighting their mother, Sado Tomoko, over Tarou’s love. In fact, Tarou has developed the theory that because his sister and mother dote on him so much – bordering on wincest – he has started to enjoy being insulted, hit, etc., by other women. Good theory, except for the fact that his late father’s heirloom consisted of… a pair of handcuffs, a whip, candles and a ballgag. A cursed bloodline indeed.

Tarou attends high school now, and as fate has it, a girl who is pretty familiar to him is in his same class – Yuuno Arashiko, the girl who awoke his masochism. She doesn’t seem to have any friends and for some reason is often late.

Fortunately, his best friend, Hayama Tatsukichi, is also in the same class. Tatsukichi’s hair is dyed blond, and he looks like a delinquent – but he is, in fact, a top student. Apparently, he changed his looks to avoid being bullied, and it worked. Tarou is really fond of Tatsukichi. After Tarou’s masochism awoke in front of everyone, Tatsukichi was the only one who remained his friend.

But alas, being a masochist is no good thing now that Tarou is in love. He wants to confess to a girl, but fears he masochism will ruin everything, so first he needs to get over it.

As for the girl, he doesn’t even know her name. They call her “Shihori-hime”, and often walks past the convenience store where he works.

Tatsukichi has heard about the Second Volunteer Club, being devoted to solving people’s problems. Tarou decides to go and seek for advice.

He enters the club room and introduces himself to the club president, Isurugi Mio, a cute blond girl who believes herself to be God. For some reason, she seems to have heard about Tarou, but before he can say anything he realizes there is someone else in the room: Yuuno – so he decides to leave.

But the pushy Mio-sama won’t let him go without hearing his request first, and, being pretty aggressive toward him, the masochist Tarou can’t help but submissively comply, while asking her to humiliate him. Ever since, she will start calling him “Butarou” (buta = pig) and, given her personality, he’s more often than not enjoying being humiliated or hit by her.

But no matter how disgusted she is at his masochism, she will try to grant his wish. The following morning, Tarou notices that Mio is dressed as a maid and is swinging a bat trying to hit him with baseball balls. If pain exists to avoid fatal injuries, she will teach his body not to make it pleasurable by risking his life. Although Tarou tries to avoid the incoming balls, one of them hits him… in his crotch, and he faints – he suspects his own masochism prevented him from avoiding the ball.

He wakes up in the sickroom. Next to him there’s the doctor, Onigawara Michiru, who explains the situation, including the fact that she’s heard about him from Mio, who is a friend of hers. In fact, it is Michiru-sensei who makes Mio cosplay (she even shows him an album of her) and she suddenly starts smoking, burning Tarou’s hand with her cigarette.

Shortly afterwards, Mio asks Tarou how he would react if a friend of his had a terrible secret. Although she doesn’t give any details, Tarou thinks that if it was, for example, his friend Tatsukichi he would accept whatever it was. After all he didn’t shun him after his masochist self emerged.

One evening at work, Shihori-hime comes in but leaves without saying a word. Tarou feels this is going to be his only chance ever to confess to her and chases after her, but she starts running. When he finally catches up with her and grabs her arm, he’s surprised to find that she’s quite strong and he ends up falling on the ground. And that is the end, because his masochist self will be activated… but to his surprise, nothing happens.

Shihori-hime says then that she had wanted to let Tarou know about her secret all along. Of course, we quickly realize who Shihori-hime is… Tarou’s friend, Hayama Tatsukichi. When Tatsukichi was in primary school he used to have a girlfriend older than him, who loved to make him crossdress because she said he looked really cute. Wanting to please her, he would often crossdress. One day, however, her father had to transfer to another city, and he started to crossdress thinking she might return that way. She didn’t, but he took a liking to it. And that is the end of Tarou’s first, albeit short, love.

Tarou tells him that he’s a pervert… but that his own masochism is way worse than crossdressing, so of course he doesn’t mind if that’s his fetish. We also learn that Tatsukichi had gone to Mio for advice on how to let Tarou know about his secret.