What would you wish for if you could make a single wish? Sakura Yamato, an anti-social genius, knows his ideal wish. When at home, as he lives alone, he spends most of his time with his little sister collection, fawning over anything little sister related. Other than them, his only other conversation companion is a stuffed rabbit memento of his long dead older sister. But one day, the rabbit starts speaking out of nowhere, and claims its feeling for Yamato won't lose to anyone else. After transforming into a woman with rabbit ears, she states she is his sister, coming from Heaven to give him a single wish from God.