Keep your enemies closer!
Takanashi Nao's best efforts to bait her older brother Shuuske into developing a sister complex have failed so far. She's even teamed up with her greatest rival Iroha to stave off class rep Mayuka, who has Shuusuke eating out of her hands.
But now a new player has entered the arena: a hot college chick named Richika, who has a twisted predilection for corporal punishment. Is Shuusuke the luckiest guy in the world, or the most pathetic?