幼い頃に母を亡くした音（有村架純）は、北海道で養父母と暮らしていた。一方、福島から上京した練（高良健吾）は、東京の運送会社で引っ越しの仕事に就いていた。練には、木穂子（高畑充希）という恋人がいた。ある日、練は、友人の晴太（坂口健太郎）が、旅先の北海道で拾ったというカバンの中から「音へ」と書かれた古い手紙を見つける。練は、手紙を持ち主に届けるため、トラックで北海道へ向かう。
Six young men and women who move from the countryside to the big city of Tokyo, each with their own dreams and aspirations. Among them is Sugihara Oto and Soda Ren. After her mother died, Oto was raised by adoptive parents in Hokkaido. Although she has given up on having any high hopes or big dreams for her future, she still remains positive and faces life with optimistic attitude. One day, she finds out the fact that her adoptive parents are planning to marry her to the wealthy man in town in order to solve their financial debt. Soda Ren was raised by his grandfather in Fukushima. Ren works hard on one job after another in order to earn the money to buy back his grandfather's land so that they can start farming again. By chance, Oto and Ren meet in Hokkaido and they decide to move to Tokyo to find new life to change their fate and future. However, as soon as they arrive Tokyo, they get separated in the crowds.
