Akiko lives with her daughter Chinatsu, a university student, sharing an uneventful life together.
Chinatsu is given an assignment from her university to write about the memory of her first love, while Akiko has developed some feelings for a new boss who recently started at the factory she works for.
For Chinatsu, her first love is her childhood friend, Kohki; however, she has a bitter memory of the words Kohki said to her in middle school. It became a painful lump that still sticks in her heart. One day, Akiko discovers a notice in Chinatsu’s room that Chinatsu is to be “re-tested” for breast cancer. Akiko’s anxiety and worries increase, while Chinatsu, who has never experienced a relationship or true love, wonders what the life of a future without a breast will hold for her aspiring love.
This unassuming but charming film revolves around a young woman who should enjoy the moment of “the world is her oyster” but instead faces struggles with the sudden discovery of juvenile breast cancer. The story blends both psychological lumps and physical lumps that people carry and an intricate mother-and-daughter relationship.