The cook would have complained that he couldn't start making supper because an imp had not cleared the rats out of the storage room yet, and asked you to tell the imp to do so. South of the kitchen you could find that imp, who would ask you to kill the rats, since he was afraid of being bitten. You could either refuse, in which case the imp would try and be killed, or you could clear the rats out yourself. The room only contains food and possible random low level items in a chest and couple barrels.
