50 years ago, two great masters from China and Japan competed, and it was hard to tell the winner. In the end, they decided to jointly write a secret book based on their martial arts experience, which caused a storm in the world.At the end of 2019, Zhuang Hui defeated Japanese players after a hard battle and won her first full-contact karate championship. She was seriously injured and paid a heavy price.In Japan, her family suffered misfortune due to the secret incident 50 years ago. Saori Kisaragi, who was often abandoned by her peers, worked hard in the mountains and became successful. After learning that her old enemy, the senior sister, had been defeated by Zhuang Hui earlier, she decided to come to Hong Kong.Challenge and find the mystery of the secret.The Hong Kong team announced its withdrawal from the Tokyo Olympics, which had been postponed for one year. Zhuang Hui, who had been preparing for the competition for a long time, suddenly felt like a bolt from the blue. She felt that her years of hard work had been wasted. She was so desperate that she decided to cut off all people and things related to karate. Zhihao has been working alone.Support the dojo and hope to wait until Zhuang Hui changes his mind.When Zhuang Hui left karate, he became an ordinary office worker and met his boss Darwin.Darwin's careful care caused ripples in Zhuang Hui's heart... Zhuang was told to go back to the sports hospital to pack the locker items. At this time, Ru Yue arrived and asked to compete with Zhuang. Teammate Tian Aidai stepped forward and was defeated by Ru Yue's punch.Zhuang was timid because of Ru Yue's strength and actually stayed on the spot. Ru Yue left a letter of challenge to Zhuang for the competition.