Norfolk, AD 990. Deep in the Fens, an order of holy sisters lives in quiet isolation, cut off from the outside world by a treacherous marsh known as the mere. Convent healer Hilda and her fellow nuns follow God’s path under the steely guidance of their abbess.

But when a young servant boy goes missing in the marsh, rumour and division spread like wildfire through the community and the abbess's grip falters. Where is the boy? Who took him? Why can he not be found?Then, newly arrived Sister Wulfrun has a vision: a curse is upon them and change must be brought. As the convent is swept up in a fight for its very survival, Hilda finds herself caught in her own battle between her conscience and her growing feelings for the enigmatic Wulfrun .