When they were younger, the Arisaka sisters (Hatsune and Kazuki) and the Kagura siblings (Yuuji and Marie) lived next door to each other. Their homes were so close that they could climb from their second-floor verandas onto one another's. They would always play together until the day the Kagura siblings had to move away. Ten years have passed, and the Kagura siblings are moving back! Yuuji has turned into a pervert, and Marie is no longer the crybaby she used to be?!