With the Ghost Detective's identity revealed, Alec and Nina find themselves trading favours for information, which soon has deadly repercussions… Meanwhile, Bobby and Linda come up against a cunning adversary in Dusseldorf. And a surprise ambush in a hospital leads to a breakthrough in the case but lives hang in the balance.

Dr. Crowley is arrested but continues to protest his innocence. The nets close in around Waingrow and the police aren't the only ones gathering evidence against him. A fresh testimony helps the investigation but uncovers a dark secret in Linda's past.