The members of covert antiterrorism unit Section 20 - Novin, Wyatt , Mac  and Chetri  - are reunited by commanding officer Coltrane under the pretense of rescuing Dr. Helen McCluskey, a biochemist who's been taken as a hostage in Kosovo by the Albanian mafia. But as the apparent search-and-rescue escalates, a sinister conspiracy to cover up the development of the weaponized virus unfolds, and S20 must track down the stolen bioweapon before the Albanians use it for profit. The trail leads them to Venice, where mob boss Edon has arranged a meeting with a potential buyer. Meanwhile, Coltrane attempts to extract intelligence from Edon's driver Jovan - whom he's convinced he's met before.