Oh My Goddess! Volume 12: The Fourth Goddess

A wrong number dialed from his dorm room on a Saturday night connects Keiichi Morisato to the Goddess Technical Help Line. When the goddess Belldandy shows up and tells him she will grant him one wish, he jokingly wishes that she would stay with him always. To both his and Belldandy's surprise, the wish is granted and Keiichi's life will never be the same.