White robes under the Druid moon, Midsummer's Eve is coming soon. Spells and chanting call the power To work dark witchcraft in the hour! Prue lands a summer trip to England to buy medieval books for a collector, so Phoebe and Piper tag along to the quaint village of Hay-on-Wye, in the heart of King Arthur country. While Piper reads how to make love charms from flowers, Phoebe meets the darkly handsome Niall. But she's shaken by a desolate vision of him on a windswept heath, holding an infant. Is Niall a warlock? Then Piper discovers a secret Druid ritual in progress, with Niall at the center of it! She freezes the group, and theCharmed Ones set out to discover Niall's secret. They learn that a local villager is in terrible danger from the Druids, and only a magical spell from centuries past can save her. The Charmed Ones are convinced that only a long journey can win against the Druids -- a voyage back in time to Camelot!