The team investigates an American citizen who is proclaiming his innocence after seeking sanctuary at Madrid’s U.S. embassy while still covered in the blood of his murdered Spanish boyfriend. Also, Vo and Raines continue to grow their friendship.

The Fly Team discovers they’re on the trail of a serial killer, taking the investigation, and Mitchell, to Japan to put an end to the international killing spree.

The International Fly Team is called on when a young mother flees to Hungary with her son, after losing partial custody of her son in the U.S. However, after the boy is kidnapped from his mother in broad daylight in Budapest, the team questions which parent is the danger in the child’s life

The team investigates an American journalist’s death by poison after his attempt to meet with an anonymous source in Poland. Also, Kellett takes Forrester to task for being overprotective with her during the mission.

The Fly Team works to hunt down the sniper responsible for killing an American during an attack targeting a biomedical lab in Belgium. Also, Jaeger clashes with her boss at Europol over her allegiance to the Fly Team.

A member of the Fly Team goes missing as the hunt for Greg Csonka continues in Paris. Meanwhile, Vo’s life hangs in the balance after being shot.

Special Agent Scott Forrester and his Budapest-based FBI fly team head to Croatia, after Isobel Castille enlists their help to capture an American fugitive who escaped to Zagreb with a 14-year-old girl. OA continues with the mission overseas, intent on bringing the fugitive to justice, while Europol agent Katrin Jaeger attempts to help the team secure the necessary support and access from the less-than-cooperative local authorities. The crossover starts on FBI S04E01 All That Glitters (I) and FBI: Most Wanted S03E01 Exposed (II).

The team investigates when the hijacking of millions worth of cryptocurrency en route to a safety vault in Switzerland leaves an American transporter dead and another on the run.

After a U.S. intelligence negotiator goes missing and her ransacked Paris apartment is discovered to be covered in her blood, the team is on the clock to find her before the country's nuclear secrets fall into the wrong hands. Also, Forrester finds himself drawing certain parallels to his mother's disappearance.

When an American founder of an illegal adults-only site is killed in Prague, the team is tasked to locate his co-founder, who is still on the run in Czech Republic; Kellett struggles to maintain a relationship with her mother.

When a group of Americans are among the victims of a bombing at a festival in Budapest, the team is brought in to find the perpetrators before they strike again. Also, when Vo's new beau is injured in the blast, she re-evaluates what dating truly means while in the bureau.

The Fly Team searches Bucharest for a Romanian surrogate who goes missing shortly before carrying the biological child of an American couple to term. Also, Forrester’s concern about the safety of his neighbors in Budapest intensifies.

Vo’s friend from the U.S. Navy calls in a favor to help find her missing nephew in Crete. Meanwhile, Forrester hangs back in Budapest to take care of personal business.

Kellett and the team reluctantly join an investigation in Northern Ireland, when one of Kellett's informants is arrested for his connection to a robbery and murder, and calls her to help clear his name.

After an American tourist is killed while visiting Stockholm with his girlfriend, the Fly Team must work together to take down a Swedish group responsible for the hate crime.

A couple flees to Albania while awaiting sentencing for bilking millions in COVID-19 relief funds from the U.S. government; Kellett works the case from Budapest as she and Forrester try to regain their professional boundaries.

The Fly Team and new Europol liaison Megan “Smitty” Garretson investigate when an American police detective on the Federal task force is murdered in Paris while looking into a U.S. company suspected of selling illegal weapons in France and the Middle East.

When an American businessman’s bodyguard and girlfriend are kidnapped a few feet away from him in Barcelona, the Fly Team questions if the man is as innocent as he claims. Also, Raines grows closer to Maya, the owner of the team’s favorite local bar.

When an American basketball player for a Lithuanian team goes into cardiac arrest, the team investigates along with Zoey McKenna, the new agent appointed by Dandridge.

The team investigates the death of an American lawyer working out of Budapest, Hungary, after his is killed by a car bomb; Kellett begins to grow close to Hungarian lieutenant Benedek Erdős as the critical case progresses.

The Fly Team jets off to Portugal when the daughter of a prominent American hotelier becomes the primary suspect in the murder of an employee. Also, Raines becomes concerned about Vo.

When a U.S. mercenary claiming to fight child trafficking abroad is apprehended at a remote Romanian border police outpost after the U.S. DOJ suspects his crew of embezzlement, Tate and Raines attempt to get him to flip on the leader of the group. The mission takes a turn when the outpost is attacked as they work to secure evidence.

The team jets to Bulgaria when terrorists hold hostage for millions in cryptocurrency a concert hall filled with multinational student performers and their families. Raines is intent on proving his field skills, and Forrester receives news of their dog, Tank.

When a notorious American tech tycoon becomes involved in a murder in Frankfurt, Germany, the team must chase him down amid the local protesters he's incited with his conspiracy theories on social media.

The team must figure out how to keep the U.S. attorney general safe amid a possible security breach while she's in Hungary for an important meeting.