In 1760s London, respected midwife Elizabeth Brownrigg secretly abuses her servants and ruthlessly tortures, beats and starves them. It's not until one girl is found dying from numerous open sores that this woman is finally unmasked and she is branded a monster for centuries to come.
Meanwhile, Kerry Lyn Dalton discovers while she was in jail, her flatmate, Irene May, sold some of her belongings to pay for crystal meth, which both women take. Kerry, high on meth, responds by torturing Irene to death via everything from electrocution to stabbing to bludgeoning.
And in turn-of-the-century Australia, Martha Rendell moves in with her lover, who leaves his wife for her but keeps their kids. Martha seems to have jumped out of a Grimm's fairy-tale as a wicked stepmother – she makes the children ill and pretends to swab their throats with medicine, which is really hydrochloric acid. After Martha kills three of her stepchildren, a fourth escapes and exposes Martha as a heartless sadist who got sexual pleasure from their suffering.