The team is reeling from the shocking discovery of a mole among them, and as the Soviet plot continues unabated, it is up to Wendy to give the team the break they need. Meanwhile, when Sarah finds herself in danger, Alan is forced to make a decision that can make or break their relationship. Joe has trouble of his own when leaked information threatens the investigation and the lives of the team.

In the secret world of espionage, the players are set and the fight to save Britain begins. A complex invisible war is being fought by skilled spies trained in the high stakes world of covert espionage. In 1972 London, tensions are at a terrifying peak as the world's super powers plot against their enemies. The threat: a dangerous and deadly Soviet plot, designed to bring Britain to its knees, dubbed Operation Glass. This is where The Game begins – a stylish, character-driven spy drama that explores the lives and lies of the invisible soldiers fighting a secret war.