Two workmen make an alarming discovery in an older Copenhagen apartment: hidden behind a false wall are three mummified corpses, sitting around a dining table with one empty seat left. The case quickly ends up on the desk of Detective Superintendent Carl Morck and his assistant, Assad and it is up to them to figure out, who the mummies are as well as who the fourth seat is meant for.

The Purity of Vengeance is the final, chilling instalment in the Department Q series, which present perfect cinematic renderings of Jussi Adler Olsen's blockbuster novels.