Watch Knock Out (2020) : Full Movie Online Free Zhou Si, who was so desperate in boxing, was sentenced to five years in prison for an accident. After his release, his wife died, leaving only his daughter Zhou Zi waiting for him. The young daughter was found to have leukemia, and Zhou Shi returned to the ring at the age of 36 to fulfill her daughter's wish. Even if the physical energy is exhausted, the head is bleeding, the vision is blurred, and the flesh and blood is splashed, it will continue to fight until the victory or defeat.