「當我們都是垃圾，這世界又算什麼？」

生存在社會邊緣的少年小樹，蹺家逃學在街頭被霸凌，他無處可去便放逐自己來到廢棄城，他以 為人生終於被分類，直到他遇見了一只塑膠袋－阿袋。心比天高的阿袋，一心想率領族人打出廢棄城，前進傳說中的聖地「回收站」。

偏偏小樹一點也不想離開廢棄城，原想靠著小樹護送的阿袋，只好憑藉自己的力量，任風吹遠身體，依然鼓起胸膛向前行。不料，小樹竟私下通風報信，無情的背叛破壞了阿袋的逃離計畫，一行人被送進了焚化爐⋯面對生死存亡關頭和強烈的罪惡感，小樹背水一戰力抗鐵甲車，救出阿袋。垃圾都想被回收，有沒有那麼一次，小樹也能拎起自己的心，思考何處是自己的回收站，再次尋得生命出路。

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