Aki Sora revolves around Aki Aoi and Sora Aoi, a pair of close siblings who have shared an intimate bond since childhood. During their coming of age, they each come to realize the true depth of the love they feel for each other and consummate that love in secret. They keep their younger sister, Nami, Sora’s twin in the dark about their new relationship. Nami, clueless of what is happening in her household aims to set her brother up with her best friend, Kana Sumiya. Despite these relationships Nami seems to have feelings for someone near to her too but keeps them secret.

Note: The first and third volumes will no longer be printed following July 2011 due to the Tokyo Youth Development Ordinance bill due to its depictions of incest.