"KO One 2" is the sequel to "KO One" and the fourth part of the "KO Series". Dadong (played by Jiro Wang) escorted Liu Bei back to Silver Time and Space on the order of the leader, but in the process, time and space resonance occurred. Dadong, who was hit by the violent impact, opened his eyes and found himself lying on a chair in the women's locker room. He learned from Jin Baosan that he had disappeared for ten years, and during this period, his parents, Arthur and Xiaoyu were also missing. The combat power index and KO list of Jin Time and Space also disappeared inexplicably. Dadong returned to the Ultimate Class and met Duanchangren, a school worker who sold loose cigarettes to students to make extra money at the school gate. He learned from Duanchangren that all this seemed to be related to Guava High School, and all the secrets were hidden in Guava High School. But the Ultimate Class at this time is no longer what it used to be. Now the boss of the Ultimate Class, Lei Ting (played by Pets Tseng), entered the Ultimate Class of Guava High School in the eighth year of Dadong's disappearance. He single-handedly resolved the crisis at Guava High School and was crowned the strongest king in history. Can Dadong find his parents and brothers? What kind of sparks will be created when the two former Ultimate Class bosses collide?