: New team member Shirley Dander demonstrates her skills by breaking into a high-security data center to retrieve critical CCTV footage of the suspect. Key Cast and Characters

: While the main investigation begins, Min Harper and Louisa Guy are seconded to MI5 headquarters (The Park) by James "Spider" Webb to provide security for a secret meeting with a Russian oligarch.

: The episode opens with Richard "Dickie" Bough , a disgraced former MI5 field agent, recognizing a man from his past and tailing him onto a bus. Dickie dies on the bus, seemingly from a heart attack, but managed to leave a one-word message on his phone: "Cicada" .