Bong-soo has been working as manager of a small bank in an apartment complex for three years. During his three years there, 23 years if you count his school days, Bong-soo has never been late. However, he purposely decides to skip work one day. There is only one reason. Inside a subway train that has suddenly stopped on his way to work, everyone around him reaches for their cell phones to call someone. At that moment, he realized that he does not have a single person to call.