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 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

When an NYPD officer is detained in Transnistria for aggravated assault, the fly team investigates his claims of infiltrating a sex trafficking ring being concealed by those in power; Forrester receives an unusual message from an unknown sender.

When the abduction of an American architect in Rome appears to be connected to a brewing terror threat in New York City, FBI’s Jubal and Nina join Forrester and his Fly Team in Italy as they work together to find the missing American and shed light on the terrorists’ U.S. target.

The crossover continues on FBI S05E17 Imminent Threat (II) and FBI: Most Wanted S04E16 Imminent Threat (III).

The Fly Team, with the help of their new intel analyst, Special Agent Amanda Tate, works to clean up the pieces left behind after a massive explosion rocks headquarters and their key suspect slips away.

When an ex-FBI agent suddenly resurfaces in a brutal Tripoli prison, Forrester and Powell risk everything to go under cover as prisoners to break him out; the fly team adjusts to their new and improved HQ.

The Fly Team heads to Bulgaria in search of a wanted criminal who is exploiting underage American girls. Meanwhile, Raines becomes curious when Forrester asks him to keep an eye on Powell.

The Fly Team heads to the Tuscan countryside after an American couple's son is kidnapped right outside their new home. Concerns are heightened as fingers begin to point to the mafia.

Assistant Special Agent in Charge Jubal Valentine heads to Budapest to personally help the Fly Team and the CIA take down the cartel that murdered his former girlfriend and colleague. As part of the mission, Forrester poses as an undercover arms expert.

When a U.S. ambassador is taken hostage at a TV station in the Netherlands alongside 70 civilians, the Fly Team is forced to work quickly to find out who they're up against. Meanwhile, Wes works to earn the respect of his new team.

When a televangelist on the FBI’s most wanted list surfaces in Gibraltar to seek asylum, the Fly Team’s attempts to take him down hit a roadblock as they face political stonewalling upon arrival to the region. When the predatory preacher goes after the daughter of a disciple as his next target, the team must abandon protocol to intervene.