Initially it was just a "find and get the item" plot, without explaining why you would want it. A fairly straightforward plot designed to drive something that was just a proof of the gameplay concepts.
Developing the reasoning behind things and expanding the plot proved a challenge.As an urban module, many of the traditional villains one might find in an adventure were out. No orc tribes, drow, dragons etc. No imposing temples of evil dominating the landscape either. With the player being an employee of the Shadow Thieves, I wanted to play up the intrigue that the Shadow Thieves are known for, but of course couldn't use a thieves guild as an enemy, since the Shadow Thieves already run things and you work for them.
Don't worry, I found some things. ;-)