Based on the erotic games by Jitaku Studio. Shun is a student with a troublesome constitution that makes his love flags crash instantly. When Shun muttered that he wanted to fall in love, his classmate Ena confessed her love to him. She said that if she fell in love with him after learning about his unique constitution, the flag would not be broken. She also suggested that they have sex to confirm this, and she pushed forward. Furthermore, his childhood friend Hinano, unable to bear seeing his extreme behavior, joined the battle...!? (Source: parabook, translated) Note: In the e-book limited special extended edition, Ayane Anekawa, who is more like an older sister to him than a real sister, also joins the battle for the protagonist, getting erotically close at every opportunity!? This deluxe edition also includes a maniacal H-scene with the main heroine, Ena.