Slow Horses

This British espionage novel revolves around a group of MI5 agents, known as the "slow horses," who have all messed up their careers in some way and are desperate to redeem themselves. The story takes place in London, where these agents collaborate to solve a kidnapping case involving a potential beheading broadcasted on live the internet. As the clock ticks, they discover hidden agendas and secrets. Will they make it in time to save the victim?