After a helicopter crash changes the stakes of a foreign election, a former-intelligence officer for the U.S. State Department has to choose between returning to the line of duty in order to dismantle a dangerous political movement in a war torn country as a matter of national security or his personal obligations as the head of a young family.

With the situation mounting in Iran, getting back to Luxembourg looks grim as John struggles to adjust to life and work in Milwaukee, while a driven homicide detective begins to build her case.

Homicide Detective Agathe Albans arrives in Milwaukee to interview Dennis. John must make a desperate last minute push to remain on the travel team.

John's effort to retrieve evidence brings him dangerously close to Agathe. Tom arrives in Luxembourg to help John catch his breath only to ask more of him.

Agathe's case against John begins to mount while John undertakes a desperate attempt to get his father's plan back on track. Meanwhile, Leslie's hostility toward John reaches new heights.

John returns to Milwaukee a person of interest in Agathe's investigation, while his already fragile mental state worsens. At McMillan, Stephen's recovery and a sudden promotion further jeopardize the mission.

Agathe, headed back to Milwaukee to investigate John, crosses paths with Alice. Tom receives critical new intelligence that may give him the upper hand in his plan to influence the Iranian election.

Agathe interrogates John just as Edward struggles to establish his brother's alibi. A surprise visitor joins the McMillan duck hunt in a last minute appeal to Leslie to allow John back on the travel team.

John returns to Luxembourg where his dedication to his father is put to the test, just as Agathe gathers final evidence that may allow her to learn the truth about John.