A killer intoxicated by pain. Should Alex Madison stop her-or save her? Across London, hospital patients are dying-in shockingly unnatural circumstances. A sadistic young woman is targeting them as they lie helpless in their beds, eking out every last sensation of pain as their lives ebb to an excruciating close. The killer is a sadist, but careful too, so the police bring in forensic psychologist Dr Alex Madison to track down what is clearly an extraordinary and damaged mind. For Alex, the case has a personal resonance he can't reveal: he knows pain and addiction all too well, and must fight to control his own downward spiral long enough to stop the killer's campaign of cruelty. As Alex closes in on the killer, it becomes clear that there are darker forces at work, and a connection to his previous case ignites his worst fears. When he uncovers the shocking truth behind the killer's motivations, Alex must decide: should he pursue the police's version of justice-or hunt down the sinister organisation that has warped another soul?