The "Sanjie Sage" was originally just an ordinary gang in the stagnant water city. After years of gang struggle, they eliminated their opponents one by one, became the overlord, and even formed a business alliance with the giant enterprise Ultor. And those gangsters who are called "saints" have also become heroes, and children will take photos with them. T-shirts with their gang logo are very popular. There is also an actor in the gang who is going to take over a movie with the theme of the saints' gang. Like the rap stars Snoopy Doug and Tracy Marlowe who used to be gangsters, these saints have penetrated into the mainstream society. The public regards them as guardian angels to protect street safety, but they can't eradicate bad habits such as stealing, drug trafficking, pimping and fighting, which drives them to leave the dead water city and come to new areas.

When they came to the new area, the saints showed their true colors, and robbing banks was their daily routine-this was the beginning of Mafia Saints 3. In order to make some quick money, the saints came up with a bold plan-they tried to hang the bank vault from the roof by helicopter. But there was an accident in this operation, and the saint was jailed as a result. This surprised everyone. They think that the police will only take bribes and will not do the dangerous task of fighting crime. When you are in prison, you will know that the boss behind that bank is actually the leader of a transnational criminal group called a syndicate. The saints' gang was actually jailed for stepping on their turf.

In this play, the protagonist and his men moved to the "steel port" together. In the years before the saints arrived there, Tiegangcheng often suffered from economic recession. This is a city built by blue-collar workers in factories, and the concept of zoning has never been thought of in urban planning. Urban planners built skyscrapers next to warehouses, ignoring the construction of large-scale transportation systems, and the city gradually weakened. Dead Water City also has suburban residential areas with white fences, green grass and single-family villas, while Tiegangcheng only has crowded and dilapidated single-storey bungalows. It's not just saints who look at China Railway Port City. Syndicates also smell opportunities there and try to steal the city. They transformed slums into casinos and brothels, where there is no glitz and glory, only endless evil. What is even more frightening is that there is a plague raging there.

The huge influence of the consortium has penetrated into every corner of Tiegangcheng. Philip hired hundreds of mental patients and placed them in three local gangs. Morningstar (led by Philip) is a well-dressed European gangster who smokes, just like in James Bond movies. They mainly sell arms and prostitutes, and usually use sniper rifles and submachine guns in combat. If the Morningstar gang is the brain of the dark forces in Tiegangcheng, then Luchadores can be said to be a muscle. They often drive SUVs around the southwest of the city. If provoked, they will fight with heavy weapons and hand-to-hand combat. Finally, Dex is a gang of computer experts, specializing in cyber crime and money laundering. When the gang war intensified, another force rose-they were the STAG (special tactics anti-gang department) set up by the government, which was responsible for eliminating all gangs encountered in the street, whether it was syndicates or saints' gangs.