Synopsis：Gal-sama can make anything come true. When his father remarries, Shohei Shindo gains a stepsister. That little sister is Rino Mizushima. Her appearance is the epitome of a gal—blonde hair, piercings, and a miniskirt. Shohei, who has otaku hobbies, and Rino, who speaks in gal language, should have nothing in common, but they end up living under the same roof. Even when Shohei sees Rino wearing only a bath towel, she doesn't mind and treats him in a friendly, sibling-like manner. Shohei thinks she's a shy but spoiled sister and assumes living with a gal will be tough. However, it turns out that Rino also shares the same otaku hobbies as Shohei, and their communication starts off smoothly. One day, under these circumstances, he finds himself alone with Rino in the bathroom. Her sister's body looks incredibly attractive, partly due to the close proximity in the enclosed room. As if drawn in, Shohei presses his lips against his sister's.