Futago Matomete "Kanojo" ni Shinai?

A classmate named Chikage is admired for her intelligence and good behavior, and she is a school rival. Outside of school, she enjoys playing at the arcade with a different, more carefree expression. Efforts are made to build a friendship with her both at school and during after-school time. The relationship appears to be growing closer, and Chikage eventually confesses feelings while leaving school. The confession is accepted, and mutual feelings are shared while walking home from the arcade. However, just as a romantic relationship seems to be forming, another girlfriend unexpectedly appears.