Three and a Half Heroes is a contemporary comedy. Wang Dafu, the manager of "Prometheus" fitness club, came back from the army and co-founded a fitness club with his comrades. Business is booming. In order to be in an invincible position in the competition, Wang Dafu is committed to developing a fitness mechanical horse that can realistically simulate various movements of running horses, and will soon put it into the market. Xiaoying, the sister of his comrade-in-arms, was promoted to the foreman of the fitness city. Wang Dafu has a soft spot for lively and lovely Xiaoying, but Xiaoying's heart belongs to another place. She has a crush on Hu Bin, a handsome guy who wants to get rich.

One day, Xiaoying took advantage of Wang Dafu's happiness and asked him to change careers as a singer and shoot MTV. She hoped to borrow 500,000 yuan, and Dafu generously agreed. Who knows Xiaoying's move is to help her boyfriend Hu Bin develop a "fitness cow" with stronger functions than the "fitness horse", and she urgently needs the money to make the final customization. Wang Dafu accidentally discovered Xiaoying's real purpose. Angry and sad, he vowed to stop the competitor Hu Bin's "fitness cow" from coming out, but he didn't know who Hu Bin was.

At the beginning of the annual national defense reserve recruitment training, both Wang and Hu were enlisted, assigned to the same team, drove the same tank, lived in the same dormitory, and did not know each other. Kind Xiaoying is afraid of conflict between them. He pretended to be his brother, disguised as a man, entered the military camp and lived in the dormitory of Wang and Hu. The three of them eat and live together. In the dormitory and Tanqueray, a series of misunderstandings and conflicts brought humorous comedies …