The leader of KMT government’s forces, Chiang Kai-Shek, was kidnapped in 1936 by Chang Hsueh-liang, commander of the Communist forces. The Communists wanted to fight the Japanese. Chiang was released on the condition that he had to join forces with the Communists against the Japanese in Manchuria and North China. This resulted in the commencement of the Second Sino-Japanese War.
TV dramas like the one above are meant to soothe the sore feelings and evoke feelings of patriotism among brainwashed Chinese people. It’s like a very tacky version of Rambo. In spite of the reputation-ruining effect that such TV dramas have on their actors, desperate actors from Hong Kong and Taiwan have also joined in.