Tsukiuta-the-animation Stories

With Rei no longer in Raina's life, she is able to live a peaceful life with her big sister Lina and her brother in law-Shun. Having the job of writing the sequel to Lina's love story, Raina gets introduced to Mila's younger sister and brother. But what happens with the brother sees Raina and wants her for himself when she wants nothing to do with him because of her love and devotion to Aoi. Will Raina be able to keep her love and devotion to Aoi or will Mila's younger brother break that love and devotion?