Damian Scott is sent to Mogadishu, Somalia to rescue British diplomats after they are kidnapped by warlord Huseyin Waabri. Meanwhile Michael Stonebridge adapts to his new career outside Section 20.

Scott learns that one of the hostages is a high-ranking military intelligence operative and that Waabri is planning to sell nuclear devices in South Africa.

Scott and Stonebridge track down a radical Islamic cleric in order to recover the nuclear devices, but are sidetracked by a CIA air strike and hostile locals.

Scott and Stonebridge prepare for an attack by Al Qaeda while holed up in an Algerian farmhouse with the nomad leader and the wounded courier. Meanwhile, back at headquarters, Dalton is called on the carpet for her relationship with the courier.

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.

Stonebridge seeks revenge on Craig Hanson after he turns up in Cape Town, South Africa. Meanwhile, Scott reconnects with a Mossad agent who's been following their case, but with a different set of orders; Knox hustles Evans to a secret installation and explains how he intends to turn his country into a world power.

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

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.

Knox plans on unloading nuclear bombs into politically unstable African nations, while Matlock reveals why he joined Knox.

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.

Enjoying a long-deserved vacation, Scott and Stonebridge are recalled after a fellow Section 20 member dies while pursuing the elusive terrorist al-Zuhari in Beirut. A new lead sends them into the remote jungles of Colombia in pursuit of a known associate of al-Zuhari’s and deep in territory controlled by a powerful drug cartel.

Out of options and hunted by the resourceful cartel, Section 20 goes for a longshot and attempts an assault in downtown Bogota, hoping to obtain intel on one of al-Zuhari’s key people. Meanwhile, Dalton looks for the source that exposed her team in Beirut, but discovers a surprising ally and a piece of al-Zuhari’s plan.

Although they are uncertain of others’ loyalties, the team must work with an asset in Beirut to get a lead on James Leatherby, a dangerous and unpredictable operative with ties to al-Zuhari.

Section 20 attempts a risky rescue for a potential new ally. Now veering close to the edge, but determined to find the truth, Dalton goes AWOL with a detainee.

While recovering from a shocking turn of events, Section 20 faces a different threat: a new enemy joining forces with an old one. Locke draws Kamali in closer to the team. Scott looks for an old friend, while Stonebridge gets closer to a new one.

Section 20 is torn between devoting their resources to the mission or saving one of their own. Stonebridge's health continues to affect him in the field. Al-Zuhari's network moves forward quickly, striking close. Kamali explains why yet another threat is emerging.

The team tracks stolen property to Russia, where Scott and Stonebridge continue their side careers as "outlaws." As Stonebridge's health continues to deteriorate, they discover new mysteries about a piece of Al-Zuhari's plan. Kamali worries that his cover identity may not hold.

Scott looks for an escape from Black Bear Prison, while Locke becomes suspicious of Kamali. The team races to locate Stonebridge, whose condition grows more dire when he encounters Al-Zuhari's plan firsthand. Continuing his vendetta, Ulyanov closes in on Scott and Stonebridge.

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 and Stonebridge face a new pivotal player in Al-Zuhari's plan, and with an imminent attack looming, the team resorts to questionable measures, sparking conflict within the unit.