When Yumi Fukuzawa entered the Lillian Girls' Academy, a prestigious all-girls Catholic school in Tokyo, she never imagined she would catch the eye of beautiful and demure Sachiko Ogasawara, one of the school's most popular students. Now Sachiko has offered to be Yumi's soeur, her "sister" and guide for all her years at the academy. The whole idea has Yumi completely flustered—after all, they hardly know each other! The entire campus is abuzz with rumors about the two of them, but Yumi is conflicted over accepting Sachiko's offer. While she admires Sachiko, being her soeur would also mean constantly being at the center of the entire school's attention! (Source: RightStuf)

Summer has arrived, and the students of Lillian Girls' Academy are on break! Yumi and Sachiko head out to the Ogasawara family's summer home, but what was supposed to be a relaxing vacation takes a turn for the worse when some of Sachiko's old acquaintances drop by for tea. These rich and snobby debutantes don't think Yumi is worthy of Sachiko's affection and they're out to make this summer one she'll regret. (Source: RightStuf)

Yumi and the Yamayuri Council have found two new helpers in Kanako and Toko. Unfortunately, their assistance comes with tension, as neither girl is particularly fond of the other and both seem likely candidates to be Yumi's petite soeur. Will either be a good fit for Yumi? As the school year marches on, the work for the Yamayuri Council piles up, and pressure begins to mount for Yumi to make her final decision. (Source: RightStuf)

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)