On Midsummer's Eve, 1648, England is in the grip of a civil war between a renegade king and a rebellious parliament. The struggle reaches even the remote, marshy Tidelands of the south coast. There, Alinor, a descendant of wisewomen, meets James, a young man on the run. She shows him the secret ways across the treacherous marsh, not knowing that she is leading disaster into her life. In this time of witch mania, Alinor's ambition and determination stand out. As a woman without a husband, skilled with herbs, suspected of possessing dark secrets, and suddenly enriched, Alinor arouses both envy and fear among the villagers - and they are ready to take lethal action.