It has been a long dry summer in the Black Forest idyll of Kirchzarten. When the local fire brigade is called to a burning farm shed, a volunteer is killed as a weapons cache beneath it explodes. The small community is shocked to the core.

Louise Bonì, back with Freiburg Kripo after a period of withdrawal, is assigned to the task force dealing with the case. The meagre evidence they gather points to a possible connection with German neo-Nazis or illegal arms dealers from the former Yugoslavia, but the appearance of secret service agents marking out the forest suggests more is at stake. Acting as her partner in the case is Thomas Ilic, whose allegiances are as conflicted as Bonì's.

Who is in fact working for whom? In the most challenging case of her career - and one that puts her in mortal danger - Bonì must to overcome the ghosts of her past that continue to haunt her.