The story begins with a phone call made by a college student named Morisawa Hotaru, who inadvertently summons the goddess Belldandy. Belldandy asks Hotaru to make a wish, and his half-joking wish — "I wish that a girl like you could be by my side forever" — is actually granted. As a result, Hotaru and Belldandy end up living together under the same roof, sharing their lives and experiencing the joys of love. The story unfolds from there, becoming increasingly interesting as more characters, including Belldandy's older sister Urd and younger sister Skuld, enter the scene!