Kinichi runs a ryokan (traditional Japanese inn) inherited from his parents while also working as a professional keirin (bicycle racing) cyclist. To dedicate himself fully to keirin, his stepsister, Ayumi, returns from studying abroad to become the inn's proprietress. Kinichi is conflicted by Ayumi's transformation into a mature woman. Meanwhile, Ayumi realizes she harbors romantic feelings for her brother. Then, one day, Muramatsu, the man who drove their mother to suicide, arrives at the inn. Unaware of this, Ayumi goes to gather wild vegetables for him. There, she is attacked by a man…