Shou, a rōnin student, suddenly receives a phone call. The caller is Ran, his childhood friend who used to live next door, and she's also currently a rōnin. She wants to stay in the room where Shou lives so she can attend winter cram school. Ran, whom he reunites with after a long time, still retains her old appearance but has grown into an unbelievably huge bust, contrary to what he used to tease her about. Ran tempts him by showing off her bountiful breasts in her careless sleepwear, leading them to live a sweet and erotic sex-filled life!
