"Machi" literally means "district", "city area". The game was called by their creators a sound novel.

The idea of the game is to let the players experience five days in the lives of eight different characters. They all live somewhere in the city, each one preoccupied with his (or her) own problems. Their paths might cross without them realizing it. At any point in the game, you can switch between characters, but when you do so, the day or the time of the day of the other character corresponds to the one you are currently having.

The eight protagonists are: Keima Amemiya, a policeman; Jintaro Umabe, an actor; Masami Ushio, a gang member; Yoshiko Hosoi, without a particular profession (the only female protagonist in the game); Masashi Shinoda, a student; Ryuji Takamine, a deserter; Fumiyasu Ichikawa, a writer; and Yohei Tobisawa, a high-school boy. You control the characters by making decisions for them: where to go next, how to answer to another character, etc. In many cases, there are wrong decisions which lead to a premature end (bad ending). The story is presented through text (without voices) and still shots of live actors and locations, with occasional short animated sequences.