In Episode 6, Merritt Lingard reveals to Sam Haig that someone inside the Crown Office leaked information to Finch about Kirsty, which led to attempts on her life. This raises suspicions that powerful people within the Crown Office may be involved in threatening Merritt and others connected to the case.

Merritt and Sam share a complex relationship; they meet in secret to discuss threats and concerns about the case. Merritt indirectly admits to receiving threatening emails and texts. Later, in a hotel room under a pseudonym, Merritt and Sam strip down to ensure neither is wearing a wire, which leads to them having sex, indicating a mix of trust and vulnerability between them.

Fergus is found drinking at a church by Carl and Akram. He reveals he was beaten by three men who warned him to stay away from Carl. Despite the attack, Fergus fought back and beat them up. After this incident, Fergus returns to drinking hard liquor, having previously tried to give it up.

Carl is shown trying to reach out to Jasper by leaving voicemails and arranging meetings, indicating personal tensions. Meanwhile, he is tasked with running Department Q and is actively involved in investigating Merritt Lingard's disappearance, balancing his personal struggles with professional duties.

Episode 6 explores connections between Merritt's disappearance and other crimes, including the death of Sam Haig and the unresolved Leith Park Murders. The episode reveals an invisible network of surveillance and suggests that powerful forces are monitoring the investigators, indicating a deeper conspiracy linked to Merritt's case.