Takashi, a nephew, is letting his aunt Yuko stay in his room for a few days when she comes to Tokyo to participate in a training course. "Aunt Yuko must have aged," Takashi's assumption was overturned as soon as he met her again. Takashi can't hide his surprise when he sees that Yuko is exactly the same as she was before. "I can't believe I'm alone with such a beautiful aunt for four days..." Even though he knows it's wrong, Takashi can't contain his excitement...