A British man crashes his car in Beijing and upon his return, he's accused of murder. After an incident on board, the officer escorting him begins to suspect foul play.

As Nolan fears for his life, tensions rise on board; Hana is instructed to investigate by the head of MI5 Delaney; Hana's sister starts digging into the events occurring on NCA 357.

Nolan recounts the events in Beijing; Hana continues to investigate the events on board; Jess's findings lead her to a mysterious international medical company.

Jess fears for her life when she becomes a target for both MI5 and a deadly assassin; Delaney uncovers a shocking truth that changes her understanding of events that night.

The truth about events on board is revealed, forcing Hana to take drastic action; Tennant is put in charge of Delaney's operation, forcing Delaney to break protocol.

The events of the fateful night in Beijing are revealed. Hana and Delaney hatch a daring plan, risking their lives to bring those responsible for the conspiracy to justice.

As the murder of a diplomatic courier leads DS Hana Li to London's US Embassy, MI5's Madeline Delaney receives a call about a bomb on the jet she is travelling on.

As Hana and Brody search for the killer, the embassy is put into lockdown but Fox remains one step ahead of them - meanwhile, a bomb is found on Delaney's jet.

When a second embassy guest is murdered, it's discovered that both victims were part of a panel that blamed the crash of the D-300 on Russia.

Hana finds a clue which changes everything, Delaney and Peterson try to defuse the bomb onboard the jet, and Banks and Jess uncover vital evidence.

Hana and Brody set a trap to catch Fox, Jess enlists surprising medical help to save Ruth's life, and the true architect of the conspiracy is finally revealed.

The true nature of the conspiracy is revealed as Hana and Brody overcome their personal demons and work with Delaney to deliver justice.