The tower

A long-serving beat cop in the Met and a teenage girl fall to their deaths from a tower block in London's East End. Left alive on the roof are a five year old boy and rookie police officer Lizzie Griffiths. Within hours, Lizzie Griffiths has disappeared, and DPS officer Sarah Collins sets out to uncover the truth around the grisly deaths, in an investigation which takes her into the dark heart of policing in London.