Security Minister Isaac Turner's hacked TV interview sends shockwaves through his personal and professional life, as he struggles with an increasingly fractured reality and discovers the dark secret that is Correction.

SO15 work to contain the facts of the broadcast hack while trying to uncover the bigger picture themselves. With DS Patrick Flynn in hospital, DCI Carey and the team investigate a web of politically charged clues which seemingly lead to China. As the ongoing investigation provides more questions than answers they tread carefully, interrogating every assumption and allegiance.

Meanwhile, Isaac Turner tries to clear his name by booking himself onto Newsnight for a fresh interview, only to find himself walking into a new trap.

Carey's investigation widens and she makes several important new allies... but can they be trusted?

Isaac's paranoia intensifies in the wake of his hacked TV interview, and his family ties are put to the test when claims about his 'love child' become headline news. Reporters circle the family home, forcing Simone to leave with their children – after which Isaac's outburst against the media is filmed and goes viral. Isaac's digital doppelgänger sets up an interview for him on BBC Breakfast, during which the results come in for his paternity test. S015 widen their search for the invisible assassins and recalibrate their thinking as to who might be behind the attacks. Garland discovers a new perspective on the CIA's Frank Napier and Carey feels the net tightening around her as allegiances buckle and shift.