Framed and sent to Kokuyoku Prison for embezzlement, Hina Saotome desperately wants to prove her innocence. However, just when she thought her situation could not get any worse, she realizes that she is the only woman in a prison populated by men. But she may have even more to fear from Aki Myoujin, a handsome and stern warden who is intent on punishing her for an unknown reason. Although the warden's treatment is unconventional, Hina's body soon begins to long for Aki's particular brand of discipline. But has this hypnotizing man, who has captivated her body, captured her heart as well?

Siblings Aki and Sora Aoi have been in a secret relationship ever since they confessed their feelings to each other on a rainy day. Sora's twin sister Nami—unaware that his affections lie elsewhere—decides to have him join the Fashion Research Club at school in an attempt to set him up with their classmate, Kana Sumiya. However, Nami's actions mask painful truths. While her motives appear like those of a good sister trying to help her brother finally get a girlfriend, she is harboring secret, forbidden feelings of her own.

The spring term is beginning for the students at Lillian Girls' Academy. Friends are reunited, but for the Yamayuri Council, it's a bittersweet time. Yoko, Eriko, and Sei are busy preparing to depart Lillian while Sachiko, Rei, and Shimako are doing their best to ensure that their dear sisters receive a memorable commencement. Sei's departure will leave a sizable hole in the White Roses, and filling it won't be easy. But is there anyone who could appeal to Shimako enough to become the next Rosa Gigantea en bouton? (Source: RightStuf)

Second season of 12-sai.