IBUKI SERI

Madoka Takura lost both her parents and was brought up in an orphanage, separated from her twin brother Kaoru, who was raised in another city. By chance, the two are reunited at the same college. Madoka is overjoyed to have her brother back, but then one day, Kaoru leaves a large sum of money in Madoka's care and vanishes. The police won't help Madoka search for Kaoru, so Madoka goes to a private detective, only to find that Kaoru was involved with the mafia. Was he killed for knowing too much? Rumors abound. Frustrated with the inaction of the police and the private detective, Madoka cuts her hair, gets a tattoo, and vows to join the Hafu to search for Kaoru herself. But, when the Hafu mafia boss finds out she's a woman, he offers to keep her secret... as long as she'll be his mistress...!

Nao, a 23-year-old office worker, grew up as the one girl in a household where her three brothers and parents were all obsessed with muscles. Nao managed to find a job and leave her house of meatheads, but is forced to return home when her office is struck by layoffs. However, she gets pissed off and runs out when she discovers that her room has been invaded by her brothers. Her big brother, Subaru, runs into the park to get her, but their argument is broken up by 35-year-old associate university professor Asuka Himori. The two of them end up meeting again at a marriage mixer and they end up hitting it off. Tonight's their first night together... but when Nao sees Asuka's naked chest, she can't help but run away at the sight of his muscles...!! No one said that a serious professor would be that muscular!! And it's not just his body, but his personality, too!?