After a disastrous failed hand-over from a independent Syrian liberation army unit, of the terrorist, "Omair Idrisi", Sergeant Daniel "Mac" Macallister, is imprisoned facing a court marshal for hitting his superior officer. Because of the failed hand-over mission, Col. Adeena Donovan, MI6, re-establish the disbanded "Section 20" unit. Mac, is offered a chance to join this new unit. He is quickly set on mission to recruit "Sergeant Samuel Wyatt", a deniable American operator, in captivity by General Farid. During the rescue/recruit mission, other new "Section 20" operators shows their value as members of the new team. The team is assembled in Tripoli, for a mission to capture Idrisi and as well reveal his source of money, Khalid, who transferred 5 million just before the team intervened. The team take custody of Khalid, but Omair eludes capture with help from his wife. Omair phones Mr. Ives, who is an arms dealer with the weapons for sale Omair intends to buy for the money.

Mac, Wyatt and the gang pursue Idrisi and his radicalized British wife. They seek to track him down via an arms dealer who just made a delivery to the cell leader, and was shot down by the same to get rid of loose ends. The crew from Section 20 rescues the arms dealer to find out what weapons he delivered and where Idrisi is. Later, when attacking Idrisi's compound, the US military gets involved, launching a bunker buster missile and putting the team in harms way.

As Jane Lowry surfaces in Budapest, Mac and Wyatt are forced to go undercover to infiltrate a dangerous group of white supremacists that has something she needs.

Mac and Dr. Markov are taken by white supremacist Josef and Rosa Varga to a secret militia base. Jane Lowery targets Col. Donovan. Wyatt whines about being stabbed. Section 20 takes bold steps rescue Mac and Markov.

With Markov taken by Jane Lowry, Section 20 track them down to a drug lord's mansion. Section 20 carry out a plan to stop Lowry and Markov from unleashing a deadly chemical weapon or the whole world will be at their demise.

Lowry and Borisovich continue their cat and mouse games with each other and with Section 20. As 20 closes in on Lowry and Markov, Lowry initiates a plan to set off a device in an airport. Reynolds emotes about her actions.

It's Section 20 v Jane Lowry in a race to get to Omair Idrisi. It's a mission that hurls comms officer Jensen into extreme danger.

As Lowry makes her play to rescue Idrisi from the Col. Parker's black site, Section 20 races to get him first. Jensen stoically recovers from his wounds. Reynolds continues to believe Donovan is hiding something important to the mission.

The team learns about Colonel Donovan's involvement in Project Tenebrae. Waves of PMC soldiers trying to recapture Idrisi have a running, driving, and shooting battle with Section 20. Donovan and Lowry have another face to face encounter.

The Russians are coming. Ives loses Idrisi to Russian agents. Twenty goes after the Atlas of covert British agents that Lowry stole and later hid. Stonebridge and Scott's surprise return aids Section 20 in a bold plan.

Six months after their last mission, three members of the British special-ops Section 20 team--Gracie Novin, Samuel Wyatt and Thomas "Mac" McAllister--are reunited for what they think is a routine "cleanup" exercise in Malaysia. Things get complicated when their new commanding officer, a borderline burn-out named Alexander Coltrane, learns that a British operative, in possession of intel about a downed Russian plane, has been killed in Kuala Lumpur after meeting with a covert Russian operative, Katrina Zarkova. The trail leads Wyatt, Mac and Novin to a Russian safehouse where Katrina and her team of Russian soldiers are attempting to track a mysterious "package" stolen from the plane, which crashed into the ocean under suspicious circumstances. The confrontation gets bloody when members of a brutal Malaysian triad arrive, setting off a chain of dangerous encounters in the skies and skyscrapers of Kuala Lumpur.

Section 20 forges an uneasy alliance with Zarkova in hopes of tracking down a nuclear warhead in Kuala Lumpur. High Commissioner McKitterick finds himself in an untenable dilemma, while Novin defies Coltrane's orders to settle a score.

Section 20's search for the missing nuclear warhead leads them to Goa, India, where three scientists have been kidnapped. Section 20 infiltrates a suspicious fund-raiser as Coltrane and new S20 computer whiz deal with a breach in security.

The team is forced to lean on Zarkova to commandeer high-end Russian technology, crack the encryption code and make a final foray to a secret hideout, where Vartak, Gopan and the nuclear packages await.

Section 20 journeys to the Punchan Province and connects with a DEA agent with inside intel on Zaza and Dagon. Coltrane tasks Novin with impersonating the nuke buyer in order to ascertain the WMD's location.

After ditching the seaplane they hijacked, 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. Finally, Section 20 tracks down Zaza and the nukes - as well as an unexpected interloper - in a remote compound, and all hell breaks loose. Expecting the worst, Wyatt makes a call back home, while Pavel forces Zarkova to come to terms with what happened to Alpha Group.

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. Zarkova questions Pavel's true identity, but chooses to stand by her commanding officer. Tracking Hassan to an outpost in the Indonesian jungle, Section 20 ends up facing off with Pavel and Zarkova, as Chetri zeros in on the nuclear suitcase in a Jakarta mall.

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. As Katrina weighs her allegiances, Pavel resets the parameters of the Russian plans to overthrow the Indonesian government.

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. After a brief respite with his wife, Madison, Wyatt takes a temporary security job working for Caleb Montgomery, an obnoxious military-tech tycoon, but soon finds himself thrust back into the danger zone.

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. The conflict takes S20 from a remote village in the Philippines to Saloglu, Azerbaijan, where three long-range missiles are ready to be fired on major cities in the West. Can the team stop Pavel and save the world from Armageddon?

Section 20 are reunited to rescue a biochemist who's been taken as a hostage in Kosovo by the Albanian mafia. But as the situation escalates, a sinister conspiracy to cover up the development of the weaponized virus unfolds.

Section 20 launches a raid on the Demachi family business in hopes of extracting the location of the bioweapon which leads them to an exchange between Edon and jihadist brothers Zayef and Mahir. While Mac considers a career-changing offer.

S20 is in Tel Aviv, tracing a man with stolen Russian military tech that he plans to sell to Zayef and Mahir. A notorious Israeli gangster makes matters even more complicated. Luckily, S20 picks up a highly-trained friend along the way.

Novin is forced to cooperate with gangsters, as Spencer gives the squad an ultimatum. After a stand-off with Zayef and Mahir, Spiegel threatens to blow the lid off S20's operations. A serious threat is posed to S20's alliance with Zarkova.

When Zayef's location is compromised, S20 raids the premises, leading to Mac defying orders to keep his team safe. Suspecting that Zayef plans to deploy the stolen military tech during a U.N. conference in Munich, S20 sets out to stop him.

Long after the incident in Munich, Wyatt and Novin reunite with Mac, who has since left the military. But while he lives out a seemingly idyllic existence with his wife and daughter, his violent past haunts him.

Spencer joins S20 to take down Zayef for good. But when intel leads them back to the Demachi's, S20 finds itself embroiled in a feud that may expedite Zayef's plans and place military-grade weapons in the hands of terrorists across Europe.

S20 plans to storm a freighter carrying weapons, but when Spencer administers a kill order, Coltrane grows suspicious. As members of S20 contemplate following their conscience, Zayef divulges intel that could drastically change their fate.

With Chetri in the wind and Carolyn on their tail, Novin, Wyatt and Coltrane are blacklisted and left with scant resources. S20 seeks the help of Russian allies to combat Russian foes, and the hunt for Zayef's hard drive marches on.

After receiving shocking intel from an unlikely Russian informant, S20 decides to reunite for one final mission to track down Arianna and avenge their comrades. This time, however, they're doing things a little differently.

Spencer joins S20 to take down Zayef for good. But when intel leads them back to the Demachi's, S20 finds itself embroiled in a feud that may expedite Zayef's plans and place military-grade weapons in the hands of terrorists across Europe.

It's Section 20 v Jane Lowry in a race to get to Omair Idrisi. It's a mission that hurls comms officer Jensen into extreme danger.

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. Zarkova questions Pavel's true identity, but chooses to stand by her commanding officer. Tracking Hassan to an outpost in the Indonesian jungle, Section 20 ends up facing off with Pavel and Zarkova, as Chetri zeros in on the nuclear suitcase in a Jakarta mall.

The Russians are coming. Ives loses Idrisi to Russian agents. Twenty goes after the Atlas of covert British agents that Lowry stole and later hid. Stonebridge and Scott's surprise return aids Section 20 in a bold plan.

The team is forced to lean on Zarkova to commandeer high-end Russian technology, crack the encryption code and make a final foray to a secret hideout, where Vartak, Gopan and the nuclear packages await.

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. After a brief respite with his wife, Madison, Wyatt takes a temporary security job working for Caleb Montgomery, an obnoxious military-tech tycoon, but soon finds himself thrust back into the danger zone.

Mac, Wyatt and the gang pursue Idrisi and his radicalized British wife. They seek to track him down via an arms dealer who just made a delivery to the cell leader, and was shot down by the same to get rid of loose ends. The crew from Section 20 rescues the arms dealer to find out what weapons he delivered and where Idrisi is. Later, when attacking Idrisi's compound, the US military gets involved, launching a bunker buster missile and putting the team in harms way.

After ditching the seaplane they hijacked, 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. Finally, Section 20 tracks down Zaza and the nukes - as well as an unexpected interloper - in a remote compound, and all hell breaks loose. Expecting the worst, Wyatt makes a call back home, while Pavel forces Zarkova to come to terms with what happened to Alpha Group.

Mac and Dr. Markov are taken by white supremacist Josef and Rosa Varga to a secret militia base. Jane Lowery targets Col. Donovan. Wyatt whines about being stabbed. Section 20 takes bold steps rescue Mac and Markov.

Section 20's search for the missing nuclear warhead leads them to Goa, India, where three scientists have been kidnapped. Section 20 infiltrates a suspicious fund-raiser as Coltrane and new S20 computer whiz deal with a breach in security.