The murder of Bryan Mills' sister launches him into a dangerous mission for revenge against cartel boss Carlos Mejia. A secret US intelligence agency, led by Christina Hart, covertly uses Bryan as bait to capture Mejia, and in the end recruits Bryan to become a part of their team.
Bryan gets his first chance in the field but the mission goes bust, resulting in a tragic death. The team uncovers a group of government officials skimming off of refugee funds, which also leads Christina to reconnect with a long lost love. Meanwhile, Asha shows up unexpectedly at Bryan's doorstep.
Bryan and team search for a suspected terrorist who has been taken, leading them to uncover a deeper plot within their own government. Christina receives troubling news and turns to Harry for support. Asha expresses her concern over Bryan's fixation with Mejia.
Riley's insistence to uncover the truth behind a fatal drug given to war vets results in her asset's child being taken. Bryan defies orders to rescue the girl and uncover the truth. When a break-in at Asha's apartment leaves her shaken, a new neighbor is there to calm her nerves.
Christina orders the retrieval of sensitive documents in Zurich needed to prevent economic and political disaster. But the mission to break into a bank vault turns into a three-way battle, and a race to escape safely. Meanwhile, Asha's trust in Elena proves to be misplaced and leaves Bryan vulnerable.
The ODNI is asked to facilitate the defection of a Russian FSB agent, but the agent's pregnant girlfriend throws a curve in the team's plans. Meanwhile, Christina goes off the books to reveal a mole in the CIA, and John's attempt to resolve his brother's problem with a local gang results in a spiritual crisis.
In the season finale, the FBI threatens to remove Christina from command and Bryan and John lead a rogue mission that risks everything to stop Mejia's associates before.
