Shoot 'Em Up movie plot

Mr. Smithis a cold and mysterious person who wanders the streets of the city with a gun but no one knows his past. He wanders like a shadow, dormant like a hunter. He is neither a doctor who saves lives and heals wounds, nor has any experience of being a father, but when he saw a pregnant woman who was pregnant for eight months being chased by a group of gunmen, he instinctively extended a helping hand. Although the woman still failed to escape and died in the chaos, but fortunately the baby was safe. Smith thought that this would end when the woman died, and he had no intention of continuing to mix it up, but he immediately discovered that the other party's target turned out to be the baby left by the woman. Unable to abandon the baby, Smith decided to ask for help from Donna Quintana, who is the most maternal in his circle of friends . She is a well-known prostitute in the underworld who specializes in dealing with customers of Oedipus complex. Smith struggled to get the help of this unreliable partner and began a gun battle with live ammunition. His opponent is the gang boss Hertzwants to get a baby . Smith wanted to know the inner story behind everything that happened, but even if he couldn't get the answer, Smith could still get satisfaction from the blissful killing.