落空奧運獎牌的莊惠（談善言），冀藉着參加全接觸空手道賽以挽回失落，豈料身受重創之餘更遭遇連番打擊，一蹶不振…師傅馬剛正（歐錦棠）遇車禍昏迷，醒後人面全非，紙皮道場瓦解，徒兒四散。關志浩（江?生@MIRROR)被莊惠所拒，又被逼陷入格鬥賭局之中，更與莊惠決裂。日本空手狂女如月沙織（武田梨奈）來港追尋被苦纏多年的家族秘密和殺父之仇，竟掀起武術界各方追尋潛隱五十年的中日兩大宗師合著的所在；另方面，如月為追求空手道真義而視莊惠為目標，強弱懸殊，莊惠能否重新振作應戰？又如何面對毫無勝算的仗？「紙皮道場」眾人歷遍艱辛，最後命運如何？

After the young and passionate karateka Jong (Hedwig TAM) lost at the Olympics, she hoped to bounce back by competing in full contact karate, but instead sustained major injuries from the competition which left her feeling devastated. Meanwhile, Jong’s master and dojo owner, Gong (Stephen AU), struggles through the aftermath of a tragic car accident which caused him amnesia, only to discover that his dojo had been shut down and his students dismissed. Whereas Ho (Anson KONG@MIRROR), Jong’s comrade and admirer, faces rejection from Jong and is forced to engage in underground combat, which further tears up his relationship with Jong. As fate intertwines, Japanese karate master Kisaragi (Rina TAKEDA) arrives in Hong Kong seeking vengeance for her father’s death and to uncover the truth behind their family secret, but in turn sparks a race in the martial arts world to search for the ultimate secret scroll scripted by Chinese and Japanese grandmasters. As Kisaragi continues to search for the true meaning of karate, she takes upon Jong as her rival – will Jong be able to make a comeback and emerge stronger than ever, or will this be a one-sided slaughter? What does the future hold for the dojo and everyone connected to it?