How to get this quest
Note this is a permanently missable quest.
After completing What Is It with Birds And Stealing and waiting a day, enter Trademond's guild. Desmond will make you a proposal. You can only accept his proposal with at least 10 Vice. If you accept, you get this quest.
Sneaking in the warehouse
To proceed further, give an anti-magic coating to Desmond. Note this will end the day.
Inside the warehouse, you can interact with the sparkling crates to steal a reward. Each theft gives you +1 Corruption and +3 exp from completing the quest. You are informed the content of each crate before being given the choice to steal its content. You can thus chose to not steal a crate's content if you think the reward isn't worth it.
There are 10 lootable crates. They contain:
After looting all the crates, or getting caught by a guard, the quest ends. It becomes marked as complete if you stole at last one reward. It becomes marked as failed otherwise.