A widowed mother named Riseiko has been living with her son Yugo since losing her husband. She works tirelessly to support them both, and Yugo grows up to be a promising student aiming for a prestigious university. As he nears graduation next year, they meet with his advisor Shiraishi for career guidance. After a successful meeting, Riseiko remains behind in the classroom where she learns that there are concerns about Yugo's academic progress...

夫を事故で亡くし、息子・優吾と二人で生きてきた母・里枝子。女手一つで懸命に働き優吾は立派に成長して、一流大学を目指せる学生になった。これから先は苦労も報われ、優吾が社会人になれば幸せな人生が待っている…そのはずだった。優吾の卒業を来年に控えた夏、担任教師・白石との進路相談を行う平岡親子。幸先のいい三者面談を行った後、一人教室に残された里枝子は、「優吾の進学について問題がある」と告げられて…。