Following an emotional break-up, FBI agent Will Chase (codename: Whiskey Cavalier) is assigned to work with CIA operative Francesca 'Frankie' Trowbridge (codename: Fiery Tribune). Together, they lead an inter-agency team of spies who periodically save the world-and each other-while navigating the rocky roads of friendship, romance and office politics.

The team is sent to Prague for their first official mission where Will has to seduce the widow of a notorious shipping tycoon in order to gain access to a list of criminal clients, but Frankie doubts his ability to deceive a grieving woman. Back in New York, the bureau assigns the team a new liaison, who just so happens to be the last person Will wants to see.

Will and Frankie continue to clash, and their growing pains may jeopardize the team's next mission in Rome where they are sent to prevent a terrorist attack.

Will and Frankie head to Paris where they must grudgingly pose as a married couple to infiltrate a wedding and capture a genocidal Romanian general.

While investigating suspicious robberies in London, Will hits it off with a sexy British spy, leaving Frankie with some unexpected feelings that she doesn't know how to process. Meanwhile, Jai competes with Susan over who is more intelligent, and Standish deals with a case of shell shock.

The team must return a kidnapped baby to its parents while also taking down the human trafficking network that led to his capture.

Will, Frankie and Susan are joined by Will's new girlfriend, MI6 agent Emma Davies, as they head to Spain on a mission to retrieve a case of plutonium from the wrong hands.

The team heads to Europe for a mission to transport a dangerous prisoner for interrogation, who, much to their surprise, turns out to be Will's corrupt former boss and ex-FBI director Alex Ollerman. Meanwhile, Jai helps organize a Secret Santa gift exchange for an off-season Spy Christmas.

Frankie is forced to prove herself as a leader when Will is captured during a mission to take down an international organ harvesting operation in Ukraine. Will spends his time in captivity attempting to bond with Jai, who is unreceptive. Standish seeks Frankie's help to improve his combat skills.

When an unexpected cuddle shocks everyone, Will goes to a dark place as he and the rest of the team are tasked to hunt down the culprit behind this unsettling attack.

The team goes undercover at a college to take down their new target - an engineering prodigy suspected of building a super weapon.

Frankie's commitment to cold-hearted professionalism is tested when the team's new mission to take down the head of a massive drug operation reunites her with a former guardian. Meanwhile, Jai and Standish discover that Susan has been writing psych evaluations on every member of the team, and their curiosity leads them to an unpleasant surprise.

Ollerman attempts to force the team to commit a terrorist attack for The Trust using Ray's life as leverage. Jai helps Standish deal with a revelation about his girlfriend. Will and Frankie come to a realization about their relationship.