The local steam plant has run dry, and Great-Witch Barbara has the only solution she knows: summon Arnold, a man reputed to be capable of locating the mythical fountain of water. Arnold arrives and discovers immediately that the fountain was destroyed a long time ago. The workaround requires combining ancient power with modern laboratory technology to gain access to time manipulation — traveling forward to unlock information about the past, then using that information to find a path back to the fountain as it once existed.