The Sun Party is a terrorist organization led by the Savior (played by Lin Guobin), who is skilled at developing war robots. He and his girlfriend Maria (played by Ye Qianwen) often use their developed robot 'Vanguard One' to wreak havoc. Due to the immense power of 'Vanguard One', the police often find themselves helpless. Xiao Xu was originally a member of the Hero Party but later felt deeply dissatisfied with the actions of his gang and left the organization with the guarantee of his mentor. One day, Xiao Xu unexpectedly meets A Mao (played by Cen Jianxun), an expert who develops war robots specifically for the police, at a bar. The two hit it off and become good friends. However, the Sun Party suspects Xiao Xu of betraying them, so they send their newly developed robot—'Vanguard Two', identical in appearance to Maria—to hunt Xiao Xu down. To make matters worse, the police also suspect A Mao of selling out the government, and thus send someone to capture them both. Can these two good brothers escape from danger?