A second-grade girl named Liu Yi lives in an unhappy family. Her father is seldom at home, and her mother, embittered by an unhappy marriage, has become increasingly irritable and neurotic. The mother tries to control her daughter, venting her pain and resentment on Liu Yi as a form of "retaliation." Liu Yi resents this control, but after witnessing her father’s infidelity and seeing her mother’s sorrow and helplessness, she starts to perceive the hardships women face, albeit vaguely. She feels a sense of empathy for her mother but realizes she doesn’t want to become like her or accept a predetermined future.

In the summer, Liu Yi begins to feel pain in her chest. She learns from the school nurse that she is experiencing early puberty, which is unusual for her age and will require medication. The idea of developing, growing up, and becoming an adult fills her with anxiety and resistance. However, her mother refuses to take her to the hospital. Liu Yi secretly takes medication from a classmate who is also being treated for early puberty, attempting to resist her own growth. But her mother eventually finds out and prevents her from taking the medication.

In this struggle over early puberty, Liu Yi faces the inevitability of growing up and ultimately becoming, in some ways, “like her mother.”