Calum Reed is attacked outside Thames House and a laptop containing the information of A Grade MI5 Assets is stolen. A threat is made to release the details of the agents, one of which includes Martha Forde (Lydia Leonard) who has connections to Russian Minister Ilya Gavrik, meaning the Russian/UK partnership is also at risk. In a race against time, the team must recover the laptop before any of the assets identities are revealed. Meanwhile, Harry meets Elena at the Opera House to discuss who has been posing as him, as his relationship with Ruth becomes more frail. And Tariq finds a crucial piece of information about who stole the MI5 Laptop, but can he contact Harry and get back to Thames House in time?