Aged five, Saroo Brierley was separated from his older brother and ended up alone on the streets of Calcutta. After weeks surviving alone, he was taken into an orphanage and later adopted by an Australian couple.

Although happy with his new family, Saroo couldn't help but think about the family he'd lost. Years later, he swapped the map of India on his wall for Google Earth, scouring it for landmarks he knew from his childhood. One day, he saw something he recognised.

And he set off on a journey to find his mother, half a world away . . .