This thread will continue until the beginning of Wolf (Caffery#7), leading to a certain amount of acrimony and misunderstanding between Caffery and Marley. That the two are both great detectives with screwed-up personal lives makes them seemingly perfect for each other, but theirs is a slow-burn (or perhaps no-burn) relationship.
Mo Hayder mixes things up here with a couple of investigations and a serial killer who isn't exactly a serial killer. Caffery remains an engaging, anti-social, brooding character. Another plot thread from the previous Caffery/Marley novel continues here in unexpected ways with occasional supernatural undertones. And the titular case offers Hayder's near-patented blend of horror-procedural.
Caffery even gets trapped in an empty septic tank by the killer at one point. This never happened to Philip Marlowe! Recommended.
Wolf (2015) (Jack Caffery #7) by Mo Hayder: A plot thread that started way back in Caffery#3 (Ritual) finally ends in the opening pages of Wolf. And a plot thread that began in Mo Hayder's first Caffery novel will also approach its conclusion.
Wolf is a clever procedural in which Caffery, operating alone, has to find hostages with only a partial note reading 'Please help us,' a dog with neither a microchip nor a helpful phone number on its collar-tag, and a wedding ring attached to that dog's collar.
The third-person narrative POV moves among Caffery, the hostages, and the hostage-takers. An old murder plays a part, as does Caffery's own unanswered grief about his brother who disappeared and was never found when Caffery was a boy. The oracular, often irritating Walking Man plays a part. So, too, that dog. Flea Marley doesn't appear, but she's in Caffery's thoughts.
We go into some unexpected places along the way, including a sort of closure for Caffery, and into the realm of corporate espionage and secret weapons development. All this and serial killers, Goths, and Caffery's endearing blend of misanthropy and overwhelming concern for the safety of others -- and for justice when that safety has been fatally breached. Highly recommended.