Oh My Goddess!

One day, a young student called Keichi Morisato made a wrong number and called the Goddess Office. He then meets Belldandy who appears behind him out of a mirror. She explains to him that she can grant one of his wishes. Keichi then wishes that a goddess stays with him forever. Keichi will have to keep Belldandy's true nature a secret, or else he'll be in trouble.