In Cairo at the height of the Arab Spring, hotel night manager Jonathan Pine receives a plea for help from an elegant, well connected guest. His actions draw him into the terrifying world of Richard Roper, businessman, arms dealer, worst man in the world.

On the Mediterranean island of Mallorca, Roper's life of luxury and calm is shattered. Six months earlier, Burr continues her recruitment of Pine, sending him to Devon to build his cover story.

While he continues to recuperate in Roper's villa, Pine starts to dig up secrets about the other members of the household. Meanwhile, Burr and Steadman seize on an opportunity to recruit a new asset.

Roper welcomes Pine into his inner circle, leaving Corky out in the cold. Meanwhile, Burr has concerns for the safety of her source when she suspects key information has been leaked to the River House.

A suspicious Roper gathers his entourage around him in an attempt to root out the traitor, forcing Pine to play a dangerous game. In London, Burr and Steadman face mounting opposition from Whitehall.

Roper and his team return to Cairo for the deal, reuniting Pine with an old enemy. Pine risks it all to put his plan in motion. A discredited Burr makes one last stand.