Two mob families clash in a war that threatens to topple empires and lives.

In this chilling 2-part drama, Joanne Froggatt stars as serial killer Mary Ann, a poisoner whose methods leave no visible scars, allowing her tally of victims to mount, unsuspected by a Victorian society unable to conceive of a woman capable of such terrible crimes. Traveling around the North East, she insinuates herself into unsuspecting families, marrying and creating new families of her own - before killing them, taking their money and moving on.

Downton Abbey depicts the lives of the aristocratic Crawley family and their servants in the post-Edwardian era—with great events in history having an effect on their lives and on the British social hierarchy.