Sasaoka Rio entered the teaching profession with dreams and hopes cherished in her heart. In her second year as a high school teacher, Rio's days were so stressful that she considered quitting her job.

Still, when Rio vents her complaints on a secret social media account, both venting her anger and being listened to by a gentle boyfriend, she maintains a balance between her natural energy and freshness.

The story unfolds when a third-year class suddenly lacks a homeroom teacher, so Rio is assigned to this position for the first time.