An underground artist leaves three glass cabinets in Trafalgar Square that contain a gruesome installation: the corpses of three homeless men. With the artist promising more to follow, newly-promoted Detective Inspector Grace Archer and her caustic DS, Harry Quinn, must race against time to follow what few clues have been left by a savvy killer. As more bodies are exhibited at London landmarks and live streamed on social media, Archer and Quinn's pursuit of the elusive killer becomes a desperate search. But when Archer discovers that the killer might be closer than she originally thought - she realises that he has his sights set firmly on her. He is creating a masterpiece. And she will be the star of his show.