The episode details the lives and crimes of the González Valenzuela sisters, known as Las Poquianchis, a notorious Mexican family who ran a large-scale prostitution and murder ring from 1950 to 1964. Driven by poverty and escaping a harsh father, they built their empire on deception and violence, ultimately killing an estimated 150 to 200 people. Their crimes involved luring victims with false job promises and killing those who became unproductive or possessed large sums of money. The sisters were apprehended, tried, and received lengthy prison sentences, though their fates varied. Their horrific story inspired a film and a novel.