As a 16-year-old struggling teenager, Leaf runs away from home, skips classes and ends up, mysteriously, in a peculiar place, City of Lost Things. There he meets Baggy, a 30-year-old plastic bag. Baggy never sees himself as just another piece of unwanted junk. He has a purpose in his life, that is, to lead his tribe to flee City of Lost Things. But he needs the help of a reluctant Leaf to fight the dreadful army of the Armors.