On an average night, the Met receives over 4,000 emergency calls, keeping London's 800 on-duty response cops busy from dusk till dawn. Crimes thrives in the shadows, and in the residential streets of north London, a burglar has been caught in the act. It's down to PC Waz Din to literally talk him down when the suspect is found hanging from a first-floor window. Eight miles away, on the busy streets of Soho, something sinister is lurking behind the bright lights. For the past two years, Detective Superintendent Kevin Southworth has been gathering evidence on the thieves and drug dealers exploiting the area. With the help of 400 riot-trained officers, he makes his move. After dark, London's clubs and bars come alive, but as the punters spill out onto the city streets, it's up to the cops to take the abuse from the ones who can't hold their booze. And the long night can be a lonely time for those suffering from mental health issues. Constables Ian Gray and Christine Wratten rush to help two Londoners who are feeling suicidal.