Storm Riders (FRA1), Forgotten Realms adventure for AD&D 2nd ed, by Troy Denning.
“The Horde is Riding!
The mountains rumble under the thundering hoofbeats of 40,000 barbaric horsemen. When the player characters find themselves in their path they have no choice except to flee.
Their journey takes them into the forbidden kingdom of Ra-Khati, a land of ancient mysteries and untold wealth nestled deep within the Katakoro Mountains. As honored guests they are invited to partake of its extravagance. Wealth, power, romance – anything can be theirs for the asking. That is, anything short of their freedom!
But when invaders threaten the Hidden Kingdom, the player characters are given a chance to earn their liberty. They are charged with escorting a spoiled princess and her dowry, a ferocious black stallion, to a nearby kingdom as a bribe to stop a war. Nothing stand in their way except 40,000 bloodthirsty riders and a vengeful purple dragon.
Storm Riders is the first adventure in the Empires Adventures Trilogy, and the first adventure taking place in the new FORGOTTEN REALMS campaign world territories described in The Horde campaign set. The Empires Adventures Trilogy is also set amidst the turbulent events portrayed in the Empires Novel Trilogy. This adventure is designed for four to eight player characters of levels 5-7.”