Castle Roogna (Magic of Xanth #3)

Once upon a past. . . .

Millie had been a ghost for 800 years. But now, restored by the magic of Xanth, she was again a maddeningly desirable woman. She could have had any man she wanted . . . except the one she did want, Jonathan the zombie. To grant Millie her desire, and to prove his right to rule Xanth in the future, young Magician Dor embarked on a quest for the elixir which would restore Jonathan to full life.

But the potion could be found only in the past . . . so, through a magic tap...