Rio Sasaoka, a high school teacher struggling with the pressures of her job, finds solace in a secret social media account and the support of her caring boyfriend. When she's unexpectedly assigned as a homeroom teacher to a third-year class, Rio faces new challenges that test her resilience and rekindle her passion for teaching.
Ibuki Arakuni is a high school student who is far from a model student. He has a childhood friend, Akabane Honeko, who attends the same high school as Ibuki Arakuni.
Nagumo Shuuji, a social studies teacher at Mie Prefecture’s Etsuzan Senior High School, was a former baseball player up until university when he quit after sustaining an injury. Thereafter, he worked as a sports trainer but returned to university at 32 years old in order to pursue his dream of becoming a teacher. However, his peaceful daily life goes through a change after he’s appointed to be the advisor of his school’s baseball club that is on the verge of abolition.
Kujo Rina is a chemistry teacher and the homeroom teacher for the 3rd grade D class at Horai High School. She doesn't have a bond with her students. On the school's graduation day, Kujo Rina is pushed from the 4th floor and falls down. She is able to glimpse a school uniform sleeve on the person that pushed her. At that time, she wonders why she was pushed and that she does not want to die.