Six months after their last mission, three members of the British special-ops team Section 20 - Gracie Novin, Samuel Wyatt and Thomas "Mac" McAllister - reunite for what they think is a routine "cleanup" exercise in Malaysia. Things get complicated when their new commanding officer, borderline burn-out 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 Katrina Zarkova, a covert Russian operative.

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 turns 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's search for the missing nuclear warhead leads them to Goa, India, where three scientists have been kidnapped by Gopan, a militant under orders from a mysterious "kingfisher." When one of the scientists escapes, the team catches up to him and his daughter, gaining valuable intel on Anjali Vartak, a rich Hindu with a personal vendetta against Muslims. S20 infiltrates a suspicious fundraiser as Coltrane and new S20 computer whiz Olivia Chetri deal with a breach in security.