Episode 1

Mary Ann Cotton returns home, having lost four babies in as many years. But under the weight of loneliness, hardship, and loss, she finds herself taking drastic steps with arsenic when faced with dire poverty and no prospects.

Episode 2

Mary Ann Cotton tries to make a fresh start as a housekeeper in the middle-class Robinson household. But time and again, she resorts to arsenic-laced tea to cover her tracks in an attempt to move on to a better life.