Citadel

When Sheikh Umar declares a perpetual war against the West following the collapse of Islamic State, London is plunged into the front line with a deadly jihadi assault on Downing Street. Josh Ryan, a new member of MI5's 'Orion' elite counter-terrorism team, lends vital support, and when the trail leads to Leeds, he teams up with MI5's Senior Intelligence Officer Lucy Hall to track and identify the terrorist cell. Events move at a fast pace as Ryan and Hall are forced to combat a much greater jihadi threat as Umar threatens to turn London into a radioactive wasteland.