Every day, Britain's Secret Intelligence Services are fighting an invisible war against a multitude of hidden threats. In this new series from the makers of SAS: Who Dares Wins, three former spies put a group of 15 men and women to the test to see if they have the skills and qualities required for that battle. They go through a series of exercises based on the Intelligence Officer New Entry Course: an intense, unsettling psychological experiment run by people who've been through the real thing. As their raw intelligence, powers of persuasion and talent for concealment are put under the microscope, the ex-spies judge who has the character, wit, values and moral compass needed to make it through to the end. The trainees all live together on an isolated base on the south coast of England and are monitored 24/7 by a team of former spies, known as Control, who between them have 45 years' experience working with the British Intelligence Services.