The game starts with a text message. The sender is a 17 years old girl called Bahn. She asks her audience for help to find her. As the game continues, the audience explores every corner of streets and narrow allies of the city chasing her traces with a few hints given in her texts. The places and certain milestones that the audiences will pass by are related to her personal memories and experiences. As each mission or place is reached and cleared, Ban is getting younger by year and eventually she becomes ten. Who is this little girl lost in the strange city? Does she really lose her way?