The incredible story of a mysterious nanny who died in 2009 leaving behind a secret hoard - thousands of stunning photographs. Never seen in her lifetime, they were found by chance in a Chicago storage locker and auctioned off cheaply. Now Vivian Maier has gone viral and her magical pictures sell for thousands of dollars. Vivian was a tough street photographer, a secret poet of suburbia. In life she was a recluse, a hoarder, spinning tall tales about her French roots. Presented by Alan Yentob, the film includes stories from those who knew her and those who revealed her astonishing work.