Veteran Wang Tiezhu unexpectedly returns to his teenage form and becomes classmates with his middle-aged son and rebellious grandson, bringing three generations into the same classroom. Determined to urge his family to devote themselves to their studies, he calmly takes responsibility and protects them when outsiders cause trouble. He leads his restless, study-averse grandson and his son, who struggles with academic subjects, in burning the midnight oil to study hard, gradually correcting bad habits and making up for their academic shortcomings. With his solid knowledge, he proves his innocence, wins first place in the provincial mathematics competition through years of accumulated expertise in an unconventional field, and earns a recommendation for admission to a prestigious university. Inspired by him, his grandson studies diligently and fulfills his dream of attending university. When the strange phenomenon fades, Wang Tiezhu returns to his elderly form. The family watches the flag-raising ceremony together and rediscovers their original aspirations, embodying the spirit of perseverance across generations and passing the torch from one generation to the next.