When the situation is about to reach a critical point, they are always on the front line, constantly exposed to danger: Lana Washington and Joel Nutkins, two ex-servicemen who fought side by side in Afghanistan, occupy the positions of leader and right-hand man respectively in a London police explosives disposal team. When a series of terrorist attacks rock the British metropolis, they are tasked with unmasking those responsible for these acts of violence, sometimes at the risk of their own safety.