It’s 2009, and DI Ross Blackleigh finds himself alone on a road in winter covered in blood with no idea how he got there. As far as he knows, a moment ago he was at a party at his house, and it was summer – but that party was a year and a half ago. The missing time is not the only mystery, because as Blackleigh is forced to investigate himself, he discovers a man he does not recognise or even like. A botched assassination attempt reveals the likelihood of someone on his own side working against him, so he must keep his condition secret to solve the multiplying and increasingly lethal riddles.

From this terrific opening hook, Charles Harris grabs the attention as Blackleigh begins a desperate chase to uncover the truth of how he came to be there and, scarier still, who he really is. The novel deftly switches back and forth in time between the twenty-four hours in which Blackleigh confronts the increasingly awful truths that lie behind the murder of a nurse, and a court case that places Blackleigh himself in the dock.

Room 15 is a rigorously researched police procedural, which gives the author a solid foundation from which to explore the theme of corruption as a matter of personal identity. Thrillers are often closer to horror than anyone likes to admit, and such is the case here. The novel is profoundly creepy in the best way, and the desperation of the haunted protagonist makes it a compellingly nightmarish journey.