“Nii-san~ are you excited?” Miu holds a special place in Ayato Kuon’s life as his step-sister and an important figure. They got to know each other through their parent’s remarriage, and although they had an initial awkwardness, they gradually became closer. It was during this time that Ayato discovered Miu’s experience with bullying. Unable to bear the thought of his sister being mistreated, Ayato quickly took action to resolve the situation. While he successfully saved Miu, little did he realize that his own challenges were just beginning. While outside, Miu remains introverted and reserved as she has always been, it is at home where she transforms into a lively gal. Despite Miu teasing him playfully with intimate remarks, Ayato finds it difficult to respond firmly because of his deep affection for his adorable sister. This is a story that delves into Ayato’s inner struggles and the evolving dynamics between him and Miu, who persistently employs alluring approaches.