The seventeenth volume of the Oh My Goddess! manga covers chapters 98-104.
Volume Description
Ever since a cosmic phone call brought the literal young goddess Belldandy into college student Keiichi's residence, his personal life has been turned upside down, sideways, and sometimes even into strange dimensions!
Peorth returns to Earth to try to reverse the slowdown of universal time at its source—the demon boy whose mysterious obsession with a goddess is literally bringing the world to a halt! What is the secret of his link with Belldandy—a link Belldandy is not allowed to remember?