DeKok and the Sunday Strangler opens with the strangling death of Fat Sonja, an Amsterdam prostitute of whom DeKok was fond. Soon a second prostitute is killed, and along with his assistant, Vledder, DeKok begins down a trail of twisted motives and hidden agendas.

In Dekok and the Corpse on Christmas Eve, DeKok himself is not above breaking the law to serve the interest of justice, as he engages a burglar to commit a break-in and then tampers with evidence to entrap the murderer of a young woman.