One morning, eight-year-old Haruko woke up and found herself in an unusually silent city. The cars walking around in this city are driverless, and the seesaws in the park will automatically swing up and down. It seems like she is the only one in the whole city. Where do people go? This space is exactly like the real world, but it is deserted. Haruko has always regarded that uninhabited city as a safe zone, and can come and go between the two worlds freely. Until one day a murder occurs and the uninhabited city is no longer safe... How does Haruko find the real murderer in the uninhabited city that is full of dangers?