The film is adapted from the true story of the "King of Dogs in the Northwest". In the Tianshan Forest Farm in northwest China, the forest ranger Zhu Guangsheng (played by Huang Hong) trained brave wolfhounds to prevent wood theft and poaching. He spent all his family property and continued to work hard. A stray puppy (played by Harley) accidentally walked into Lao Zhu's life. Lao Zhu named it "Rambo" and began to train it to be a forest protection dog. The extremely human Rambo soon became Lao Zhu's good helper. Zhang Biao (played by Liu Xiangjing), who was imprisoned because Lao Zhu reported him for poaching wild wolves, was released from prison and began to seek revenge on Lao Zhu and constantly threatened the safety of Lao Zhu's two daughters and Rambo. Zhang Biao's several poisonings and hunting were resolved by the witty Rambo. Zhang Biao was desperate and took Rambo away with people. Lao Zhu and the police station director Liu (played by Sun Tao) found Zhang Biao and saw a pot of dog meat on the table and were indignant. The truth is that after being robbed, Rambo fought wits and courage with the criminals and looked for an opportunity to escape in the kitchen. Fatty (played by Fei Long) and the cook (played by Qin Wei) led everyone to chase and intercept him. Rambo climbed over the wall and "flew over the eaves and walked on the wall" and finally escaped successfully. In order to give Rambo a good home, the two sisters sent Rambo to the city to be adopted in tears, and the loyal dog Rambo broke free from the chain and ran dozens of kilometers back to Lao Zhu. Zhang Biao fell in love with Lao Zhu's daughter Zhu Cong (played by Zhao Tingting), and "kidnapped" her to the Lover's Valley, vowing to change his past and show his love sincerely. Lao Zhu and his youngest daughter Zhu Lin (played by Zhu Lin) went into the mountains to look for him and encountered a car accident and were besieged by wolves. Rambo risked his life to rush out of the wolf pack and go back to report the news, and led the group of dogs back to the mountains to rescue Lao Zhu. A tragic battle between wolves and dogs was staged...