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.

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.