Long Xidan, a young farmer from Yimeng Mountain, went to work in Shanghai to earn money, but was mistaken by Longsheng's housekeeper for Long Debao's long-lost young master and brought into Long Fu. Long Xidan was forced to pretend to be the true young master, and was named the heir of the Dragon Family property and the captain of the long dart team by Long Debao, while the true young master was forgotten and became a street beggar. Long Xidan led the dragon dart team to defeat the Japanese violent group, showing national integrity, which attracted the attention of underground party member Pearl Krabs and prepared to adapt it into anti-Japanese armed forces. Long Xidan cleverly prevented Japanese spies from renting docks. When Long Debao was seriously ill, Xidan moved Long Debao out of filial piety. He found the real young master Dillon's egg and voluntarily gave up his position as a young master. In order to regain his position in the Dragon Family, Dillon Egg did not hesitate to collude with traitors and gangs, and took refuge in the Japanese army, becoming a national scum. In retaliation, Dilong Egg personally killed his new wife, Lihua, and forced his mother to death, and was finally executed by Long Debao. Long Xidan took over the love of the underground party and adapted the dragon dart team. In the Battle of Songhu, Long Xidan led a team to participate in the battle and became an anti-Japanese hero. In order to prevent the Japanese from landing, Long Debao sounded explosives to induce the explosion of the dock, and the Japanese warships perished together.