In 1539, a pregnant novice nun, Agnes Moore, ejected from her convent and staying with resentful relatives, claims to have been attacked in the ancient chapel of St. Mary del Quay on Liverpool's waterfront by Satan himself. Her former abbess, Lady Katheryn Buckeley, comes to her aid but when a young priest is found dead in the River Mersey, his right hand hacked off, Katheryn realises that Liverpool harbors some disturbing secrets.