A fishing boat in the Baltic Sea makes a gruesome find: a life raft adrift with two dead men, being picked apart by gulls. The fishermen flee, and when the raft finally washes ashore in Kurt Wallander’s jurisdiction, the bodies prove to be Latvian gangsters, horribly tortured and then executed.
Latvian police major Karlis Liepa flies to Sweden from Riga to investigate. Chain-smoking, alcohol-swilling, and tight-lipped, Karlis bonds with Kurt as only terse tough cops can. Then he flies back to Riga and is immediately reported murdered.
Karlis’s superiors, Colonels Murnieks and Putnis, invite Wallander to the major’s funeral, but they want something more: their colleague’s missing case notes. It seems that the life raft was smuggling cocaine as part of a drug ring run by former KGB officials. After Latvia’s break with the Soviet Union, some KGB agents stayed with the police, some went over to the mafia, and some did both. Karlis was apparently on the trail of a mafia mole inside his department.
Murnieks and Putnis toy with their Swedish colleague by habitually calling him “Colonel.” (“I'm not a colonel! We don't have colonels!” Wallander insists.) They bug his phone and take him on police raids in search of Karlis’s killer, finally arresting an obviously innocent journalist who once had an affair with Karlis’s beautiful wife, Baiba. The journalist immediately hangs himself in prison—or so his jailers say.
Wallander finds that his only sure ally in this nightmare of corruption is Baiba, with whom his intimacies follow their usual course. Detained by police, Baiba is rescued by Wallander, who tells the cops he has found Karlis’s case notes. He has indeed—in Karlis’s camera. But the digital images of incriminating documents do not satisfy the still-mysterious high-placed mole, who wants the originals.
Now on the run, Wallander and Baiba know that their only ticket to safety is Karlis’s original notes. Baiba guesses that he would have hidden them in plain sight in an obvious place. The police archives! Wallander breaks into the facility with the help of one of Karlis’s old pals on the force. Although he doesn’t read Russian, the sleuth manages to find the file, guided by a dropped, crushed cigarette pack of Karlis’s preferred brand, showing the major had been there.
With the documents in hand, Wallander escapes outside and is approached by Putnis, who inadvertently lets slip a clue that he is in fact the mafia mole. On the verge of shooting Wallander to silence him, Putnis is felled by a police sniper, planted by Murnieks, who turns out to be a good guy.
In the aftermath, Wallander learns that Putnis, afraid of being exposed, lured Karlis to his death. After parting with Murnieks and paying Baiba a farewell visit, the angst-ridden Swede returns to his orderly homeland, where criminals are corrupt and cops are just trying to be cops.