Section 20 forges an uneasy alliance with Zarkova in hopes of tracking down a stolen nuclear warhead in Kuala Lumpur; the group grows frustrated when Police Inspector Amy Leong pulls them off the job after a false alarm.

Section 20's search for the missing nuclear warhead leads them to India, where three scientists have been kidnapped by a militant; the team gains valuable intel on Anjali Vartak, a rich Hindu with a personal vendetta against Muslims.

As Wyatt is tortured by Vartak's henchmen, Mac presses her corrupt lawyer to hand over an encrypted hard drive that might hold clues to the whereabouts of a pair of "nuclear suitcases."

Novin and Zarkova find themselves at the mercy of corrupt police, while Mac and Wyatt take temporary refuge in a local village; Coltrane finally learns the location of the suitcase nukes, but the revelation comes at a high price.

As Wyatt convalesces, Coltrane, Mac and Novin embark on a covert, 24-hour mission inside Russia to extract an FSB analyst with potentially vital information. Katrina questions Pavel's true identity, but chooses to stand by her commanding officer.

Coltrane defends his decision to go rogue with S20. After tailing Hassan and the nuclear suitcase to a deserted shopping mall in Jakarta, Wyatt and Novin face down threats from Komodo soldiers and, later, Colonel Aldo and his insurgents.

In pursuit of Pavel, Section 20 clashes with two other Russian renegades, Natasha Petrenko and Artem Orlov, as they attempt to purchase sophisticated software designed to short-circuit a ghost satellite containing precious cargo.

Section 20 faces an ultimate dilemma as it battles Pavel and his team of Russian turncoats for keys to Soviet-era missiles thought to have been destroyed years earlier.

Scott and Stonebridge are stranded in the Alps with the mercenaries in pursuit. Scott knows that the CIA hide weapons caches across Europe, so they find a telephone at the farm of a retired Austrian soldier Oscar (Wolf Kahler) to call Christy Bryant (Stephanie Vogt), a past acquaintance from Vengeance, for the location of the nearest one, at a nearby dam.

The daughter of Thailand's British ambassador is kidnapped, so Stonebridge, Scott and the rest of the team sign up for another do-or-die trying adventure.

Locke takes Section 20 off the radar, as they defy Whitehall to travel to Geneva where he is convinced that Li-Na and Kwon are preparing to attack the United Nations HQ.

Scott and Stonebridge try to keep their promise to protect Ester; Richmond and Martinez follow an Al-Zuhari associate; the team sets out to stop an infiltrator before he reaches a populated area.

Scott has a serious talk with his son whilst the rest of Section 20 form an uneasy alliance with a couple of CIA mercenaries as they go after Shiro and Mei Foster.

In the season finale, Stonebridge and Scott are in a race against time to find a pair of suicide bombers targeting Budapest.

Knox extricates a political leader from a Zimbabwe prison, and the unit tries to catch up with the escapee by tracking his activist daughter.

Locke works out that his long-time friend is working with the dangerous Yakuza and Office 39. Scott needs protect his son after they find themselves enemy fire.

In order to stop Knox, Scott comes to Bryant for assistance. Meanwhile Stonebridge has trouble focusing on the mission as he is bent on revenge. Section 20 get assistance from South African police to stop Knox's plot.

Section 20 try to track down the real culprits behind the embassy attack, starting with getting information from gangster Ray McQueen.

The battle with Li-Na is now in Europe, as Section 20 look for a way to get back on her trail. Locke ends up getting an unexpected chance to confront his nemesis.

The team find out that Li-Na is planning to mount a nuclear attack in Europe. Locke puts himself in the firing line after he neglects the mission in order to avenge his son's murder.

In Kosovo, Stonebridge, Scott and four hostages find themselves in dire straits after being double-crossed by KFOR soldiers and the drug lord Hasani.

Scott and Stonebridge head to Chechnya to track down Latif and a stockpile of chemical weapons.

The trail of the missing nuclear triggers leads to Cape Town, South Africa, where kidnappers abduct the children of an expatriate munitions expert to force him to cooperate.

Unrest spreads after the assassination attempt on political leader Lutulu, while Stonebridge questions the shooter in an isolated police station and looks for a safe way out.

Scott and Stonebridge make a major mistake and fall into the clutches of North Korean agent Li-Na, leaving Locke having to defy orders to get them out.