Lion tells the story about Saroo (Sunny Panwar), a 5-year-old boy living with his mother, brother and sister in Khandwa, a province in the middle of India. One day he follows his older brother to a job. Due to unfortunate circumstances Saroo falls asleep on a moving train and ends up all alone in Calcutta. Saroo doesn’t know the name of his village, doesn’t speak the Bengali language and is forced to sleep on the streets. Surprisingly he manages to survive, not without difficulties, and he finally ends up in an orphanage. Approximately one year after he got lost, Saroo is adopted by Sue and John Brierley (Nicole Kidman & David Wenham), a loving Australian couple.
Twenty years later Saroo (Dev Patel) moves to Melbourne to study hotel management. While lunching with some of his Indian friends a childhood memory pops up when he sees jalebi, an Indian delicacy. That’s the moment Saroo reveals that he was adopted. One of his friends makes the smart remark that he cas use Google Earth to search for his hometown and family.
Starting from this point Saroo dedicates his life to finding his home and family. Partly at the expense of the relationship with his girlfriend Lucy (Rooney Mara) and adoptive parents. After a long search he seems to have found the village he was born and travels to India.