Harry is handed over to the CIA, ready for deportation to the US, but events are thrown into turmoil when the team receive detailed knowledge of an attack on the UK.

Harry kidnaps his CIA counterpart and interrogates him. What Harry discovers alters his suspicions of who is behind the attacks on the Anglo/Russian partnership.

Two former inmates are released from jail and set to launch an attack in London. Erin and the team must step in at the eleventh hour to prevent massive loss of life.

MI6 receive word that radioactive material has been detected at an airport, while the home secretary invites Ruth to dinner to discuss a possible new role.

Top-level secrets are stolen when Calum is mugged outside Thames House. A random robbery or a theft-to-order? Either way there are lethal consequences for the agents.

Ghosts from the past come back to haunt MI5 chief Harry Pearce, prompting a shocking revelation about his time as a spy during the Cold War.