Xie An, a modern rebellious high school student, accidentally traveled back to 1984 after an argument with his father and became a seven-year-old elementary school student. He accidentally met his father Xie Jianjun when he was a boy, and after helping him, he was taken home as an orphan brother. From then on, he called his grandfather "uncle" and his grandmother "aunt", and he and his father were the same. Xie An relied on modern criminal investigation knowledge and the "era resonance" ability of a mysterious copper whistle (touching old objects can reveal the afterimage of the past) to help the police grandfather solve strange cases: a radio drama imitation murder case, a credit union master key theft case, a supply and marketing cooperative director's secret room murder case, a serial disappearance of children, and an old wall-hiding corpse case. He also helped his father realize his dream of becoming a soldier, took in Xiulian, a survivor of the Zhao family massacre, and gradually uncovered the shocking conspiracy of the mysterious organization "Tongmen". The bronze whistle became hot, and Xie An returned to modern times. As a high school student, Xie An continued to track down the Tongmen organization in modern times. The bronze whistle's ability was upgraded to "time and space retrospection". Together with his grandfather who was a policeman and his father who was retired, three generations joined forces to finally reveal the true identity of the owner of the Tongmen and the secrets of the three bronze whistles, completely destroy the Tongmen organization, and reunite the whole family.
