From "Adventure Summary and Background:"
The Coryani province of Balantica grows the grain that sustains the Empire, and indeed much of the rest of the world. The val'Dellenov family controls this province and its bountiful farmlands, but they cannot manage it alone. For generations, five human families, collectively known as the grain factors, have been overseeing the harvesting, transportation and distribution of these massive amounts of grain. They have become well-established nobles as a result, and while they are constantly struggling against one another for increased prestige with the val'Dellenovs, they have always been loyal to their patrons and to the Empire…until now.
For reasons that are not immediately apparent, one of the grain factors, House Otrecto, has decided that it needs to hoard massive amounts of grain, and quickly. To this end, they have begun stealing grain from various locations throughout Coryan and storing it at a number of secret locations. One of these locations is an ancient Myrantian fortress hidden beneath the sands of the Forsaken Wastes. Otrecto agents in the fortress and the nearby towns have tricked a local hobgoblin warlord into doing their dirty work for them, leaving the agents to collect the grain undiscovered. Unfortunately for House Otrecto, the PCs have come along at exactly the wrong time.