OK, here's enough without breaking any copyright laws:
Dragons are near-mythic creatures who left the continent to journey "west." Close to 2000 years ago, the dominant race (humans) and allies were attacked and defeated by a sudden incursion of Half-dragon, half-demon servitors called the Dramojh - they were left behind, and grew in strength. They created a slave-empire hell-on-earth, and over centuries stamped out all resistance.
Cue 1700 years later. The Giants across the sea to the east, exploring westward, came across the Dramojh evil empire. Incensed with righteous fury, they kicked Dramojh booty (because in addition to the slaves lacking any will to resist, the Dramojh had grown decadent over the millenia.) They EXTERMINATE the Dramojh. They freed the humans,etc. and set themselves up as stewards, rebuilding the land, cities, schools... (think the allies and West Germany post-WW2).
Cue 200 years later, the Giants are still in charge, and most humans think it's a good thing. However, there's starting to be contention. Thanks for all you've done and all, but...
There are gods, but they don't necessarily exist (think in Eberron flavor), ritual and ceremony is a HUGE part of life for all peoples because of its power, and there are a number of threats, from secret organizations, monstrous humanoid militaries who are also recovering from the Dramojh's wake, things uncovered in the evil ruins of the Dramojh, etc.
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If you follow the updated timeline, there's a big plot twist. Don't know if your GM wants you to know this, but:
[sblock]The Dragons have returned. They tell the Giants, "thanks for helping with the Dramojh problem. Now get out." The Giants haven't quite given an official response yet...

[/sblock]
So hopefully that gives you an idea of the main plotline.