Newly divorced Jo is delighted to move into her best friend´s spare room. The high-tech luxury flat is managed by a meticulous Home Assistant, Electra. Late one night, Electra says one sentence that rips Jo´s fragile world in two: ´I know what you did.´ And Jo is horrified. Because in her past she did do something terrible. Something unforgivable. Now she wants to destroy you.