In the winter of 1977, the bell of the resumption of the college entrance examination broke into the cold winter that had frozen for ten years.
Ning Xiaoshuang is a child of the Black Category 5. Her father is a mathematics professor who was sent to a labor camp, and her mother relies on cardboard boxes to support the family. She works as a temporary worker in a textile factory, hides a copy of "Advanced Mathematics" left by her father, and secretly calculates under a kerosene lamp, eager to use knowledge to wash away the humiliation of her family.
Song Weidong, an educated youth, had a "thorn on the head", a scar on his eyebrow bone, and his right leg was disabled due to saving someone. The son of a teaching assistant at Tsinghua University, he spent six years building canals in Hongqi Commune during the day and writing calculus formulas on the dirt with tree branches at night.
An accident of catching a thief brings two young people abandoned by the times to meet. He taught her how to solve problems in the snow, and she forged his official seal to qualify for the college entrance examination. When Ning Xiaoshuang's father's academic notes were confiscated and burned, and when Song Weidong had his right index finger broken by the commune, they discovered that——
