The series will focus on counter-terrorism policing and the outstanding work of the London Metropolitan Police's bomb disposal team. The story tells that a terrorist campaign in the summer threatened the security of the capital, and the bomb disposal officers were busy at the forefront of emergency operations to find out who was behind the explosion before the number of casualties increased. Vicky McClure plays front-line police officer Lana Washington and Adrian Lester plays Joel Nutkins. Both are former soldiers who served together in Afghanistan and have a close relationship. They are now bomb disposal personnel, known as "Expos/Disposers" (tentative translation).