Um agente de segurança e um agente do MI6 unem forças após um ataque terrorista. Suspeitam da existência de um infiltrado enquanto correm contra o tempo para impedir uma conspiração de maior envergadura que ameaça Paris.
The terrorist group Voltov kidnaps microbiologist Rachel Moss and forces her to create a deadly biological weapon. Zara and Vincent, who were monitoring Yuri Mishkin, the group's leader, must intervene to prevent the virus from being released and save Rachel.
Back in London, Zara realizes there's a mole within MI6. No longer knowing who to trust, she cuts off all official contact except with Karen, to whom she confides. In Benghazi, Rachel has to treat Vincent, who is seriously wounded. Vincent promises to help her escape if she saves him.