The documentary picks up four months after the attempted assassination, when there was still no sign of the source of the Novichok. Salisbury re-opened after months under lockdown - only for civilians Dawn Sturgess and Charlie Rowley to fall ill in nearby Amesbury. As the death of the former turned it into a murder investigation, questions began to be asked about how well the UK reacted to such unprecedented Russian aggression and the stark security lessons that were learnt