Mark Tartaglia and his colleague Sam Donovan are still reeling from their battle with the serial killer known as the Bridegroom when they are called upon by DCI Carolyn Steele to investigate a suspicious death in Holland Park. In the wee hours of a chilly winter morning in central London, a victim in her late twenties or early thirties lies stripped naked, her body kneeling in the snow. Her ankles have been taped together, and there is bruising on her face and scratches around her mouth. It's also possible that she was sexually assaulted.

According to toxicology reports, the woman reeked of booze as though she had been raped and killed by two different people and that she was drunk and had rough sex, whether consensually or not. When a positive ID reveals that her name was Rachel Tenison, an art dealer who was last seen at work in the West End a few days ago, the Barnes Murder Squad is suddenly plunged into a deepening mystery that centers on a secretive world of sadomasochism and kinky sexuality.

With his usual attention to detail, Mark can see no evidence of a struggle or anything suspicious having gone on in Rachel's flat, although it doesn't look lived in -  almost like a theatre set with none of the usual feminine clutter. Rachel's brother Patrick Tenison, a local MP, can shed little light on Rachel's movements in the days leading up to her death, speaking of his sister with an off-handed dispassion as though he were just a neutral third-party observer in her life.

Patrick does, however, tell Mark that Rachel had been intimate with Richard Greville, her boss at Christie's Auction House, but the affair had run out of steam a while ago, probably because Greville was married and would never leave his wife. When Sam questions Greville and he has an alibi for the evening before the murder, the investigation turns to Rachel's best friend, Liz Volpe.

Liz was about to inherit Rachel's flat on Camden Hill, but from the way she talks there was something odd about her relationship with her best friend. Mark is positive that Liz is hiding something, even protecting someone.

As the monochromatic images of the naked and bound Rachel kneeling in the snow keep flashing through Mark's memory, he becomes certain that she couldn't have been killed by a stranger, the way her body was tied up, almost ritualistically and requiring careful preparation. Then there is the strange poem by Charles Swinburne found on Rachel's body, with its hints of masochism, flagellation and paganism. Whatever the killer meant by the poem, the murder was clearly premeditated.

When the three-year-old murder of Catherine Watson, a university professor who coincidently taught Swinburne, is linked to Rachel's death, the Barnes Murder Squad become certain that a serial killer is on the loose. As with Rachel, the killer seems to have taken his time and tortured Catherine over a period of several hours. Like Rachel, she also had a mystery caller the night before she died, indicating that both women knew their killer.

As this compelling page-turner races forwards, Tartaglia and the rest of the team are torn between needing to know the terrible secrets of Rachel's sexual life and the realization that she had increasingly manipulated those around her. Her world was a fragile house of cards, the games she insisted on playing threatening to devastate and bring down her friends and colleagues.

As with Forbes' debut novel, Die With Me, this latest Tartaglia installment plays out in a bleak and wintry London, chapter upon chapter building a foreboding, almost gothic atmosphere. Writing in a muscular and fast-paced prose style, Forbes pens a compelling drama that comes at us from every angle: from the disaffections and insecurities of detectives who betray their positions of authority to the various suspects and acquaintances of Rachel - and Catherine - who gradually line up, all desperate to provide an alibi.

In the end, treachery comes from one of the most unexpected places, and poor vulnerable Sam finds herself yet again the victim, walking straight into the lion's den of misplaced passion and obsession in the novel's shocking and unexpectedly devastating finale.