In 1965, a couple was doting on their newborn twin boys when a notorious gangster named Crazy Kung was transported as a imprisoner in the same hospital. Crazy Kung escapes and hold one of the twins hostage, which led the twins being separated and grow up without knowing the existence of the other. Ma Yau is now a concert pianist and conductor while kidnapped Wan Ma is adopted by a woman and works as an auto mechanic who is passionate about care race and martial arts. 26 years later, the brothers unexpectedly reunite and accidentally switch roles, causing both caught in ackward, confusing but not less dangerous situations.