Documentary exploring life inside HMP Frankland, the men's maximum security prison in Co Durham, which has housed some of the country's most notorious criminals, including Peter Sutcliffe, Ian Huntley and Delroy Grant. The programme recounts some of the violent prison attacks that have taken place over the years, including one so horrifying that it forced a staff member to retire. Later, an ex-prisoner shares how he passed the time in Frankland's segregation unit by organising a quiz through the cell windows