Stripped of their old identities, the raw recruits meet for the first time in London on day one. They receive their first briefing from their 'tutors.' With no time to unpack, they are sent on their first mission: a real test used by Mossad, the Israeli Secret Service. They are given just 10 minutes to talk their way into a stranger’s flat and be seen by their trainers drinking a glass of water on the balcony. After only 24 hours on the course, the recruits must learn a vital lesson: every spy can break under pressure. Without warning they are abducted from their safe-houses in the middle of the night and interrogated by intelligence professionals. They must stick to their cover names and avoid giving away any details about their real lives.

The wannabe spies hone their skills at 'going grey' - the art of mingling in a crowd without being noticed. The trainers instruct them in using effective body language and building an instant rapport with strangers. The recruits then embark on their toughest mission yet, which will test their skills of persuasion, nerve and the ability to think on their feet. They attempt to gain access to an office building (during working hours) and take photographs of confidential documents without getting caught.

The greatest spies in history are those who blend effortlessly into any new environment. Will the recruits be up to the job? Their mission brief is simple – go undercover, assume a new identity and fool those around them into believing that they’re someone they’re not. Their trainers, real former spies, are monitoring their progress and have a devious trap to find the recruits out. Will all of them make it through?

The recruits continue their quest to master the spying game. Following the dismissal of the first candidate, the remaining recruits struggle with their feelings as they are taught the ruthless art of cultivation - how to lie and manipulate others. Whether it’s gaining confidential information from a hotel receptionist or getting a total stranger to look after a sensitive document for them, the recruits will need all their skills of charm and persuasion to pull it off. The recruits’ final, highly confidential mission is to win the trust of each other’s nearest and dearest. They are to manipulate the person to gain entry into the family home and photograph the master bedroom without being detected.

The art of surveillance is a core skill for any would-be spy. Working in teams, the recruits practice the basics of following targets without being noticed or drawing attention to themselves. The would-be spies are tested as the trainers watch and judge them on their triumphs and failures. For their latest mission, the recruits must use all their spy skills and put their professionalism to the ultimate test in a one-on-one surveillance mission in Brighton. They don’t realize until the last minute that their target is actually their closest friend or family member whom they haven’t been allowed to see since starting the course. If they allow their personal feelings to compromise the mission, they risk being thrown out of spy school.

Having mastered observation and surveillance skills, the recruits are now faced with their first 36-hour mission. They have to mount a surveillance operation on the occupants of two target houses. They must break into target properties, plant secret cameras and bugs and fix tracking devices to cars. Split into teams, the recruits’ relationships are put to the test as they share cramped and claustrophobic living conditions for the duration of their stake-out.

The art of cultivating an agent is the core work of an intelligence officer. Teaming up in pairs, the six remaining recruits take temporary jobs at a barber shop, a gym and a clothing store. Their fellow employees are unaware that their new coworkers are spies. After working undercover cultivating and befriending a complete stranger in order to turn them into their agent, it is time for the recruits to complete their mission. They will have to manipulate their target and get them to cross the line of morality, by persuading them to lie, sign a fake document or help them in a legally questionable way.

After six weeks on the course, the recruits have learned to rely on each other and have come to appreciate the value of trust and collaboration. But this time they will have to embrace the darker side of spying: betrayal. Two recruits are the subjects of internal investigations and it is up to their fellow spies to set a trap and gather incriminating evidence. For some this will mean the end of the course. Spy school is closed and the recruits are about to graduate to their final mission, but first they must pass the ultimate test of loyalty. They find out what it’s like when a spy thinks their organization has turned against them, and that they’ve been left out in the cold.

The tension mounts as the four remaining recruits are exposed to their most dangerous scenario to date and their loyalty is tested to the limit. The trainers have assigned all the recruits a mission that is truly impossible. Each recruit is led to believe that, having failed, they must leave the project. The recruits must keep their heads among false sex scandals and offers of vast sums of money from PR consultant Max Clifford. At their most vulnerable, will they give in to greed and hunger for instant fame, fall into the trap and betray their organization by selling secrets to the tabloids? As in the real world of espionage, any recruit who betrays their organization will face the consequences.

The final three recruits have been tested to their limits and beyond in their bid to come to grips with the spying game. With their training now complete, the trio must undertake a final confidential mission abroad, working against professionals. Without the support of their trainers and unsure if they can trust each other, they must complete their mission without being detected by their target or the local authorities. There is also a final twist in the tale, as the recruits are followed by a real professional, an ex-spy, who uses his professional expertise to trick them. Only one recruit will return from this mission as the perfect spy.