Berlin. Four friends. One extreme idea. One of the most gripping thrillers ever written. Kris, Tamara,Wolf and Frauke set up an agency called Sorry. An agency to right wrongs. Unfair dismissals, the wrongly accused: everyone has a price, and Sorry will find out what it is. It's as simple as that. What they hadn't counted on was their next client being a cold-hearted killer. But who is the killer and why has he killed? Someone is mocking them and hell is only just beginning.