The series introduces the concept of "guest stars", a new main character in addition to the main female character each season. Callum Turner from the first season will not return. The new season will once again question whether seeing is necessarily believing. Britain is under siege: hacked news feeds, manipulated media, and interference in politics. Senior Inspector Rachel Carey, who has established herself in the UK's "correction" department, finds herself in the middle of a new conspiracy and facing a new target. But how can she solve the case when she can't even trust her closest colleagues? Compared with the surveillance issues in the first season, the situation is even worse. The story will tell about the "invisible" killer, the terrifying rise of deep fake technology, the growing tension between the government and big tech companies, and the corruption at the core of the British media. Holliday Grainger returns to play the female protagonist Senior Inspector Rachel Carey. Paapa Essiedu ("I May Destroy You") plays the new guest male protagonist Isaac Turner MP, a young rising star politician who aspires to the top position.