Kahina Zadi and Anders Harnesk are desperately looking for a connection between the bestial murder of Frenchman Pierre Carnot and the helicopter pilot Kambo. On a notice board in a shop Anders happens to see a note with Kambo’s name and the number 20 on it. A note with Carnot’s name and the number 21 is also found. Anders and Kahina realise that this is just the beginning.