DC Alice Armitage is investigating the murder of a patient on a psychiatric ward. In a facility where security is paramount, she must try to discover how this was able to occur and also who could have possibly been able to carry this out. Could it have been one of his fellow patients? One of the members of staff? An outsider who has managed to gain access? Alice’s work is cut out, not least because the detective isn’t exactly on the case – she’s one of the patients in the ward.

I loved the premise of this book and found Alice a fascinating character. Despite traumatic events in her past placing her in the psychiatric unit, she is convinced that the police are not doing their job properly and so uses her skills to conduct an investigation of her own. Feeling that she has identified the killer, she uses her contacts in the outside world to assist, only to find her theory derailed several times.

Despite the setting, Rabbit Hole is packed with dark humour as we meet a plethora of characters, each given a nickname by Alice. Some of her fellow patients are an absolute joy, their well-described quirks making it easy to visualise what life was like in this unit.

For fans of the author’s Thorne series, you will be pleased to see that there are a few cameo appearances of characters you may recognise. I particularly liked the subtle Phil Hendricks reference quite early on in the book.

There are plenty of twists and turns along the way with numerous red herrings thrown in for good measure. The ending was not expected with part of it making me question everything I had read! This is a great standalone from Mark Billingham, an author who I don’t think has ever written anything less than a brilliant book.

With thanks to Little, Brown and Net Galley for my copy.