Our main character is a young and hopeful novelist. He has been uselessly wasting his life away following the death of his younger sister, Yoshino. Our hero is forced to stay in an old decrepit apartment provided by his publishing company. Here, he meets Marino, who remarkably resembles his young sister. They begin living together in the apartment. Shortly after, our hero learns that Marino is the half-sister to Ayane, the chief editor of the magazine he writes for. Marino proves to be poor at housework, but she is completely devoted to our hero. Notwithstanding Marino's cheerfulness, our hero comes to find out that she holds a very dark and bitter memory she is unwilling to recall. Enjoy your short summer with Marino! Following the feature presentation, you will find a side-story about the girls from "Natural-Both Body and Heart" and "Natural 2-DUO-." You will find more information concerning Ayane's life, along with the characters Chitose and Sora. [Edited from gamelexgs]