ICS discovers that toxic sludge is being trucked across the border and dumped in the Canadian wilderness. They follow a trail to a vicious criminal gang, who gain control over Gray and his father. As Gray struggles to save his father, he sets off a chain of events which bring about the season's shocking conclusion.

The American President's upcoming visit to Canada has the ICS Squad on full alert. Working with DHS Agent Liz Carver and the Secret Service Advance Team, ICS sifts through hundreds of threats and uncovers an assassination plot by a Lebanese terrorist, working for the Iranian Revolutionary Guard. But as Slade digs deeper, he discovers the trail they've been following is an elaborate electronic smokescreen created by a sophisticated hacker. To make matters worse, an internal security leak means the real assassin is always one step ahead of the Squad.

Kessler and Carver hover near death while Gray hunts down Layla's killers. A bloody highway shoot-out with the crime mob 'Ndrangheta has left Major Kessler and Agent Carver fighting for their lives. The Squad is forced to the sidelines, as Special Counsel Louise Tilden investigates the role of ICS in the much-publicized tragedy. Meanwhile, Gray, who has been suspended from duty, sets out to avenge the murders of Layla and his father Dougie.

Maggie becomes personally invested in the plight of two young Filipino children, victims of a human trafficking scheme.

The frozen body of a Russian man is found in a railway car triggers an ICS investigating of the smuggling of blood diamonds via the Canadian north.

The Prime Minister of Quebec feels threatened and ICS follows the trail of a former FLQ bomber to a small town straddling the Canadian/US border.

Khali becomes personally involved in the case of Mina Diwan, a strong-willed Indian 18-year-old who arrives in Canada looking for her "runaway groom". Using a false identity, Anwar Singh has married Mina in the Punjab and stolen her family's $50,000 dowry. Unwilling to return to her strict Indian family, Mina seeks out Canadian relatives to sponsor her for citizenship, but they too disapprove of Mina's modern ways. ICS learns that one of Anwar's previous brides is missing and presumed dead. When Mina goes missing, Khali and the Squad must race to save her.

ICS face escalating gang violence when a U.K. Tamil gang member enters the country for his son's life-saving surgery.

Sent to Afghanistan to provide border security advice, Kessler and his American companion are kidnapped by hostile forces.

MI6 horns in on the ICS investigation of tainted heroin and an African drug smuggling ring.

Kessler's daughter Zoe helps Yuan Dao, China's star figure skater, escape from the Chinese Secret Service. Dao claims to be a freedom activist who will face torture and execution if returned to China. Having fallen for the skater and his story, Zoe takes Dao to ICS, where Kessler faces political pressure to hand him over to the Chinese. Zoe and Dao escape again, this time from Kessler.

A kingpin in Mexico's Los Zetas drug cartel is en route to Toronto to meet his new distributors - the ultraviolent street gang, MS-13. Ramon Esteban - the new flame of Kessler's ex-wife Terri - is a Mexican journalist whose articles on Los Zetas have put him on the cartel's hit list. When Kessler, Carver, and Gray attempt to transfer Ramon from Terri's shelter into protective custody, MS-13 launches an all-out attack. Kessler must fight back with an unlikely team of warriors.

Three American army deserters claim refugee status in Canada, and ICS must deal with the personal and political fallout.

A deadly assassin shows up in Toronto, drawing ICS into a web of international political intrigue.

Agent Bianca LaGarda escorts seventeen year-old Ali Jabir, a Canadian resident with ties to terrorists and just released from Guantanamo Bay, back to Canada. Kessler and ICS enter questionable moral territory as they use Ali as bait to capture notorious terrorist Nasim Mujab, Ali's childhood friend. Slade - assisted by CSIS agent and language expert Khalida Massi - uncovers an impending terrorist attack on Toronto. At the official inquiry into the 'Ndrangheta shoot-out, the future of ICS is at risk.

Now back on active duty, DHS Agent Liz Carver tracks a murder suspect, the notorious white-supremacist Cole Thorpe, to Canada. Kessler assigns Gray to infiltrate Thorpe's British Columbia-based neo-Nazi operation. Carver still blames Gray for the 'Ndrangheta debacle and her own injuries. When Gray learns the neo-Nazis are planning a devastating act of racial terrorism, Carver must work with him to stop it.

Kessler suspects the Canadian military is complicit in the cover-up of a scheme to smuggling cheap Afghan heroin into the country.

Kessler sends Khali and Darnell to Montreal to investigate claims that a celebrated golden Buddha was stolen and illegally imported to Canada. But the protesters - a Buddhist monk and an idealistic school teacher - turn out to be as mysterious as the Buddha's smile. Khali goes undercover to discover their true intentions.

In a Toronto coffee-shop, an African refugee recognizes the brutal Congolese warlord who raped her and enslaved her son. As they struggle to keep the warlord behind bars, ICS uncovers a deadly conspiracy that links coltan smuggling in the Congo to a powerful multinational based in Canada. Hard-nosed politico Jack Hardacre takes over as Minister of Public Safety, and takes a strong dislike to Kessler. And rebuffed by Kessler, Charlotte takes solace elsewhere.

An eco-terrorist sabotages an Alberta pumping station and Gray and Layla must untangle an international corporate espionage scheme.

Counterfeit pharmaceuticals kill an American rock star. ICS searches for the Canadian link but Bianca LaGarda takes matters into her own hands.

When wealthy philanthropist Benjamin Herzog is murdered, the prime suspect is his financial advisor Cyrus Church. Church has engineered a massive Ponzi scheme to defraud his investors of billions. Foreign operatives determined to recover stolen funds are also looking for Church. And complicating matters, Church's new trophy wife is Svetlana Karpov, a Russian stripper from Kessler's past. ICS's newest agent, Khalida Massi, finally gets a chance to prove herself in the field.

A snuff film is confiscated at the Maine-New Brunswick border, and Carver finds the body of the film's victim Stateside. ICS traces the video back to the vicious biker gang, Satans Guard. Maggie goes to the east coast to see her estranged daughter Kim whose boyfriend, a former member of the gang, is eager to inform on his former associates. Meanwhile, ICS learns of a cross-border serial killer - who has just set his sights on Kim.

As international leaders debate Arctic sovereignty, Kessler and ICS fight to rescue a Canadian submarine crew trapped under the polar ice.

While tracking a fundamentalist Christian sect moving "child brides" across the border, Gray meets his match.