This game won't necessarily involve the setting to a great degree, but a pre-made setting is an easy way to add a little flavor to an otherwise plain module.

The core of Eberron is that if it's in (a given edition of of) D&D, it's in Eberron. In addition Eberron adds its own features and twists:
The Last War: a century-long, continent-covering war has recently ended, only after an entire nation, Cyre, was wiped out in a magical catastrophe of unknown cause. Scars from the conflict are still fresh.
The warforged: a "race" of intelligent constructs, made for war. The treaty ending the war granted the warforged their freedom, but they face uncertainty and prejudice.
Dragonmarks: Semi-hereditary magical birthmarks, that grant magical talent to those who possess them. Thirteen families have leveraged theirs to gain and control mercantile power. Rogue groups with "aberrant" marks struggle for power and recognition of their own.
Magic is part of everyday life: Many people live with a constant low-level of magic and magical items around them. A smith might have a magical forge that burns extra hot. A scribe might have a magical quill that writes for him. A tailor might know a minor spell that guides their needle. There are magical trains, magical carts and magical ships that sail the air or the sky.
The gods don't walk among us: Eberron has many gods and religions based around them, and divine power is real, but the gods do not appear to involve themselves personally in the world.

Eberron in 4th Edition is still a "points of light" setting. There are many dark places of the world, where only adventurers can hope to make their way.
This message was last edited by the GM at 21:26, Mon 23 Nov 2020.

One of the most important locales in Eberron is Sharn, the City of Towers. It's the largest city in the world, and consists of hundreds of enormous towers clustered close together and stretching into the sky.

The city has a population in the hundreds of thousands, but the size of the city is such that the average population density is very thin. This results in Sharn being a points-of-light setting within a points-of-light setting: the population is clustered into many close, little communities within the city, all separated by large regions that are not to be traveled lightly. Gangs are on the lookout for easy prey and for those transgressing their unwritten laws. Spies and operatives conduct business left over from the Last War - or related to the next one. Mad artificers operate from forgotten laboratories. Various monsters of all types wander through hurriedly abandoned regions, where lost treasures gather dust.

The classes of the city are, roughly, arrayed by altitude. The very rich and influential, such as the heirs of dragonmarked houses, live at the tops of the towers, or even in towers that float in the air above the city. The very poor live near the bottom, perhaps never seeing the sky their entire lives, but only the grimy undersides of criss-crossing bridges. In the middle are those reaching for more, or just trying not to slip into ruin.

Though it is rich and prosperous and magnificently illuminated with magical lights, Sharn is, ultimately, as shadowy a place as any in Eberron. People who venture far from their huddling place do well to be equipped with weapons and magic or to be in the company of those who are.
This message was last edited by the GM at 20:32, Sat 31 Oct 2020.

In reply to DM Paul (msg # 2):

That’s an intense location! Are we starting out here?

In reply to Frug (msg # 3):

Yes, "Kobold Hall" is, like many other dungeons, located in Sharn.

(Other games might not portray it the way I do. I think the intent might have been for there to be bustle and intrigue in the upper city and dungeon crawling in the Depths below the city, but someone did the math based on some official numbers and found that the population was tiny for the volume. And I feel like this enables all the benefits of points-of-light.)

In reply to DM Paul (msg # 2):

Great start Paul

Sharn is a hive of corruption, but it has four primary criminal groups.

The Boromar clan is a halfling gang, with interests in smuggling and thievery.

The Tyrants are a group of changelings who are known to deal in assassinations and other crimes that benefit from being able to look like someone else.

Daask is composed primarily of monstrous humanoids: ogres, goblinoids, kobolds, medusas, harpies, etc., as well as dragonborn, goliaths, shifters, tieflings and kenku.

House Tarkanan consists of people who have so-called "aberrant" dragonmarks, that do not conform to those of the thirteen recognized houses.

Not every individual who could reasonably be a member of one of these gangs is, which might sometimes put them at odds with members of their own kind who are.

None of these groups have a direct hand in the threat at the core of this adventure, but there are the groups that might come to mind if someone was thinking about crime in Sharn. Not that the PCs are at a level where they'd want to get on the bad side of any of these groups anyway.
This message was last edited by the GM at 21:28, Mon 23 Nov 2020.