Background
The game is set in the Forgotten Realms in the country of Amn on the Sword Coast. Primarily around the city of Athkatla and the areas around it. Athkatla conforms to the Forgotten Realms handbook in most every way. I've reiterated some of the more important points below just to make sure they're crystal clear.
Athkatla is run by money. Plain and simple. Laissez-faire capitalism is the rule and if something can be had it can be had for money in Athkatla. Athkatla is run by a city council of 5 elected officials. Everyone in the city knows that the council is ineffectual and the city is actually run by the guilds.
Every worthwhile merchant venture in Athkatla has a guild. Some of the larger guilds have great wealth and power while the very largest are like governments unto themselves. Here is where the true politics of the city happens. The guilds vie with each other for dominance over their individual areas and influence in the areas that they affect. For example: While the Merchant Seaman's Guild is the undisputed controled of sea borne freight they compete with the Slaver's Guild and Fisherman's Guild for Ships and Rigging from the Ship Builder's Guild. The Merchant Seaman's Guild will attempt to curry favor from the Shipbuilder's Guild so that they can take delivery on ships and supplies earlier and at better cost than the other Guilds. In return, the Slaver's Guild may raise prices for the Ship Builder's Guild in an attempt to influence decisions. Alternately, they may try and gain favor by giving gifts and tribute.
Sometimes violence will erupt between two guilds. Some guilds even have ongoing wars with each other over areas where their influences cross. As a result, the larger Guilds have standing security forces which outnumber the Athkatlan city guard. This, of course, means that the city guard will often turn a blind eye when a prominent guild is caught breaking the law. The guilds respect this and try to keep their machinations hidden as much as possible. A poor public image can be bad for business. Instead, the Guilds work secretly gathering information and checking up on rumors. Silently eliminating the competition while trying not to get eliminated themselves. As always, business is very good.
Business in Athkatla is driven by the guilds and the great houses. The great houses are extended "families" who have influence in several different guilds. Much like the crime families of 1920's Chicago, they have their own politics, struggles and wars just like the guilds. Alliances between families are very important and their information networks rival those of the guilds.
Magic is very common in Athkatla. It's a sign of wealth and influence but it is also seen as very dangerous. As a result, arcane spellcasting is illegal in Athkatla unless you are a member of the Slaver's Guild or the Mage's Guild. Person's demonstrating arcane spellcasting ability who can not show membership in one of these organizations will be imprisoned. Still, if you are a member of one of the two guilds you command a respect above and beyond the norm. It's traditional in Athkatla for a great house to send their second born child to the Mage school North of town for training in the arcane arts. Having an established Mage in the house goes a long way toward establishing power.