In this two-part series, we look at a backburn that got out of control during the Black Summer fires of 2019-20. Investigative reporter Harriet Alexander looks at what went wrong. How the backburn escaped and destroyed a large part of the upper Blue Mountains. And the subsequent battle by locals to find out what happened. This is episode one: From the outside.Subscribe to The Age & SMH: https://subscribe.smh.com.au/See omnystudio.com/listener for privacy information.