In the aftermath of the most devastating conflict mankind had ever experienced, the tiny island of Shikotan became part of the Sakhalin Oblast... and on the unhealed border in this remote corner of the world, friendship among children from two different countries timidly blossomed, striving to overcome language barriers and the waves of history. Inspired by true events. On August 15th, they told us we had lost the war. At that time, we did not really understand. Then one day, everything changed. Many soldiers, wearing uniforms we had never seen before, arrived on the island. That was the day I met Tanya. (Source: Production I.G)

When 16-year-old Nanako Misonoo enters the prestigious all-girls Seiran Academy, she believes a bright future awaits her. Instead, the unlucky girl finds herself dragged into a web of deceit, misery, and jealousy. On top of that, she is chosen as the newest inductee of the Sorority, an elite group whose members are the envy of the entire school. Having none of the grace, wealth, or talent of the other members, Nanako quickly draws the ire of her jealous classmates—especially the fierce Aya Misaki. To cope with her increasingly difficult school life, Nanako recalls her days through letters to her former teacher, Takehiko Henmi, whom she affectionately calls onii-sama (big brother). She also finds comfort with her four closest friends: her childhood friend Tomoko Arikura, the sociable but erratic Mariko Shinobu, the troubled musician Rei Asaka, and the athletic tomboy Kaoru Orihara. An impassioned drama about the hardships of bullying, Oniisama e... chronicles a young girl's harsh life at her new school, as she endures cruel rumours, heartless classmates, and countless social trials.

The story centers around three characters—Uesugi Kazuya, his twin older brother Tatsuya, and Asakura Minami. Kazuya is the darling of his town as he's talented, hardworking, and the ace pitcher for his middle school baseball team. Tatsuya is a hopeless slacker who's been living the life of giving up the spotlight to Kazuya, despite the fact that he may be more gifted than him. Minami is the beautiful childhood girlfriend and for all intents, sister from next door who treats both of them as equals. Society largely assumes Kazuya and Minami will become the perfect couple, including Tatsuya. Yet as time progresses, Tatsuya grows to realize that he's willing to sacrifice anything for the sake of his brother, except at the expense of giving up Minami to Kazuya. And thus the story is told of Tatsuya trying to prove himself over his established younger brother, how it affects the relationship between the three, and both brothers' attempts to make Minami's lifelong dreams come true.

Momiji is an average girl until the day she finds she is the descendant of the great Kushinada family. Only she, with her Kushinada blood, can stop the Aragami, demonic plant-like monsters threatening to destroy Japan. Along to help her is the TAC, and a possible love interest in a young man named Kusanagi. (Source: ANN)