Ichiko Sakurai, a 30 years old novelist, has a crush on Saotome, who is only in his twenties. This caused a heated discussion between the 5 personas controlling Ichiko's brain every time she is around Saotome.
The two main characters, Ichiko and Saotome, live on the Toyoko line. Their nearest stations are Shimaruko and Motosumiyoshi. These stations are about 2 km apart from each other.