In February 2022 in north London, a group of men were arrested and charged for castrating and mutilating other men. Their leader was a Norwegian national, Marius Gustavson, who called himself the Eunuch Maker.

As Marius Gustavson and his co-offenders receive lengthy sentences, Marcel Theroux meets the survivor who initiated the investigation and others who reveal the scale of the crimes and question the motivations behind them.