Firewall, by Henning Mankell trans. Ebba Segerberg

Cyber-terrorism in small-town Sweden

Kurt has been keeping me up late of recent nights; not a habit I usually maintain with ageing, doubt-ridden, irascible Swedish blokes. But then Kurt Wallander is a homicide investigator on Ystad's small-town police force in the rural Skane region of southern Sweden, and some of his most productive ruminations occur in the small hours. All too often, these are followed by a realisation or phone call that hurtle him out of bed to snoop around flats in the dead of night, or examine a horrifically pulverised corpse, or have a shoot-out in a pitch-black ploughed field. He's often up most of the night, and never misses the 8am conference back at the police station to review the bewildering evidence. No wonder he is so knackered.

Kurt has been keeping me up late of recent nights; not a habit I usually maintain with ageing, doubt-ridden, irascible Swedish blokes. But then Kurt Wallander is a homicide investigator on Ystad's small-town police force in the rural Skane region of southern Sweden, and some of his most productive ruminations occur in the small hours. All too often, these are followed by a realisation or phone call that hurtle him out of bed to snoop around flats in the dead of night, or examine a horrifically pulverised corpse, or have a shoot-out in a pitch-black ploughed field. He's often up most of the night, and never misses the 8am conference back at the police station to review the bewildering evidence. No wonder he is so knackered.

Firewall cracks along at a punishing pace. This places two cards in the author's hand. First, this thriller has a long, convoluted plot. Its officers respond succinctly to events, sketching ideas in the sand before fresh trouble sweeps in to re-form their hypotheses. Second, this is Henning Mankell's eighth novel featuring Wallander, which makes it a mature relationship. Mankell is able to give assured detail to the tensions and loyalties distracting Wallander within his team.

His trusted but aspiring deputy seems to be grassing Wallander's unorthodox decision-making to Chief Holgersson, who has already tried to suspend him for whacking a teenage girl who had confessed to murder. Wallender feels almost obsolete in his ignorance of computers; and it is raining, or at least very foggy, in his sex life. This misery Mankell craftily manages to draw into the mechanics of his plot, rather than observing as an aside to Kurt's beleaguered circumstances.

A boldness for weaving big ideas into seemingly local crimes has often given Mankell's novels an expansive atmosphere. A decade ago, in The White Lioness, Wallander foiled a plot to assassinate Nelson Mandela and foment civil war in South Africa, pursuing KGB assassins through the misty coastal landscapes of Skane. Last year, The Return of the Dancing Master did not feature Wallander but did uncover a Europe-wide resurgent neo-Nazism that festered in Swedish rural hamlets. Firewall very effectively realises the plausible threat of global cyber-terrorism, initiated in sleepy Ystad.

Inevitably, coherence of detail, rather than grandeur of design, gives Firewall its adrenalin charge. There are far fewer credibility gaps than in previous works, in which tension has sometimes dissipated like water from a cracked pitcher. Mankell is confident enough to leave hanging a few loose ends, which embed a satisfying ambience of dirty realism and unresolvable business: the routine laundry of fraying relationships with colleagues and friends.

Mankell's forthcoming work will explore his own connection to Mozambique, where he directs a theatre and campaigns on Aids, but I am already hankering for a return to Ystad and a few more sleepless nights traipsing after Kurt.