In a Lonely Planet(孤独な惑星)

Mari lives a comfortable life as a single woman. She has a nice job at a company and resides in an apartment in the suburbs of Tokyo. A couple lives next to door to her. Mari can hear them argue or making happy conversations everyday. One night, when Mari comes back home, she sees her next door neighbor sitting in front of his door and shivering from the cold. He locked himself out.