Follows London widow Cora Seaborne who moves to Essex to investigate reports of a mythical serpent. She forms a bond of science and skepticism with the pastor, but when tragedy strikes, locals accuse her of attracting the creature.

The Essex Serpent follows newly widowed Cora, who, having been released from an abusive marriage, relocates from Victorian London to the small village of Aldwinter in Essex, intrigued by a local superstition that a mythical creature known as the Essex Serpent has returned to the area.