A dangerous chase. A sadistic killer.

DS Lucas Walker is on assignment for the Australian Federal Police, and it couldn't be more personal. This is his last chance to take down Stefan Markovich - leader of the Vandals outlaw motorcycle gang - the man who has managed to evade justice ever since Walker uncovered his drug operation in Australia's remote interior.

Having tracked Markovich to Berlin, Walker heads to Germany to lure his nemesis out of hiding and into custody. And there is another draw for Walker in Berlin: he finally gets to see Barbara Guerra again. After meeting in Australia two years earlier, Lucas and the German detective have formed a long-distance friendship ... and maybe something more.

Now Barbara is leading an investigation into a suspicious death that has cast a dark shadow over the peaceful lakeside community of Mildersee. Everything about the horrific scene tells her that it's murder. When a second gruesome death occurs, Barbara realises she is hunting a killer who poisons their victims and then watches them die in agony.

As Walker and Barbara grapple with their complex and dangerous cases, they are finally forced to confront their feelings for each another. But is there any chance of a future together, when they lead their lives in completely different worlds?

The fourth gripping instalment in the bestselling DS Walker series - full of shocking twists and thrilling turns - follows Lucas to an explosive showdown, far from home. For fans of Jane Harper, Cara Hunter and Chris Whitaker.