On the eve of a historic nuclear-weapons summit with a North Korean delegation, Robin Foster, the British Ambassador to Thailand, learns that his daughter Chloe has been kidnapped by a ruthless Bangkok gang led by an expatriate named Ray McQueen. Racing against the clock to locate the girl, Scott, Stonebridge and their Section 20 team – including boss Philip Locke and agents Julia Richmond and Kim Martinez – track the thugs through the canals and streets of Thailand. When their efforts stall, Foster ends up following his own instincts, despite the chance that things could get worse before they get better.
Reeling from a deadly explosion, Locke and Section 20 regroup at a new crib in Bangkok, with Scott and Stonebridge tasked to bring in McQueen – who is also targeted by Changrok, captain of a corrupt SWAT unit at the Bangkok PD. The boys soon realize that Chloe's kidnapping is the tip of a much larger plot, one involving a North Korean crime syndicate, Office 39, and it's ruthless Bangkok leader, Lee Dae-Ho
Shiro, son of the aging boss of the Yakuza crime syndicate, ascends to power with the help of a duplicitous Lei, and vows revenge on Section 20 for his father's murder. With the location of his latest Bangkok crib compromised again, Locke suspects there's a second North Korean spy in town. Stonebridge, Richmond, Martinez and Locke fend off waves of attack from the Yakuza, while Scott finds his long-anticipated visit with son Finn less than idyllic. After its latest bloody face-off, Section 20 heads to a private island, desperate to learn what the Yakuza have that the North Koreans covet.
Hoping to track down the Yakuza's shipment of vanadium - a metal crucial to the making of nuclear weapons - Scott strikes a deal with Faber and Mason, a pair of bounty hunters looking to kill Shiro. Having convinced Finn that he's not a drug dealer, Scott sends his son on a bus to safety and heads off to rendezvous with his mates, who've got all they can handle in a firefight at the Kokura Foundation, a legal front for Shiro's drug operation. As Locke tries to uncover the truth about Shiro and his father, Mei looks to slip out of the crossfire, again.
Posing as Russian construction workers, Scott and Stonebridge cross the North Korean border in an attempt to blow up a strategic munitions site, but find their route paved with obstacles. Mission accomplished for now, Mei returns home and reunites with an old flame. In Bangkok, Finn chats with the wrong stranger, and ends up running for his life. As North Korean officials celebrate the Yakuza's nuclear bonanza, Lei worries about the dangers ahead - concerns that seem legit when a pair of interlopers arrive to spoil the party.
In North Korea, Mei - now embracing her real name, Li-Na - is tasked by her mentor, Moon Young-Su, to pry a confession out of Scott and Stonebridge, using Finn as leverage. Meanwhile Locke and Martinez recruit a familiar face in Russia to help get them into North Korea and attempt a dangerous rescue operation.
In Vienna, the cloned phone of a Russian mob leader named Myshkin leads Locke, Nina, Scott, and Stonebridge into a public plaza - and a rendezvous between Kwon and Oppenheimer, the world's most dangerous bomb maker, and a man Locke dearly wants to apprehend. Later, Scott and Stonebridge crash a daring bank heist orchestrated by Kwon and Li-Na, in search of a one-of-a-kind document that holds the key to their diabolical plans.
With the assistance of Nina, Scott and Stonebridge track down Matthias, an eccentric young encryption analyst hired by Kown and Li-Na to access vital nuclear-material codes. Later, Locke comes face-to-face with his nemesis, while Scott and Stonebridge intercept the interceptors of a key convoy.
On the trail of Li-Na and Kwon, Locke, Stonebridge, and Scott play a hunch and head to Geneva, where a nuclear disarmament conference is taking place. A face-off between Section 20 and the North Korean renegades ends in a flurry of gunfire - and an inconceivable betrayal.
Gone to ground after a daring helicopter escape, Scott and Stonebridge try to elude a team of mercenaries in the Swiss Alps in order to bring a traitor to justice. With their ammunition nearly spent, the boys get a helping hand from an unexpected source before ending up in a final, epic fight to the finish.