One night in Lankhmar, Gray Mouser and Fafhrd are summoned by their patron wizards, Ningauble of the Seven Eyes and Sheelba of the Eyeless Face, unusually working together, to carry out a mission. They are required to enter the Plaza of Dark Delights to obliterate a bazaar that has been established there by the Devourers, alien merchants that magically mesmerise customers into buying high priced merchandise that is actually worthless trash. But Mouser arrives before the others and is enticed into the bazaar. Fafhrd, aided only by the Blindfold of True Seeing and the Cloak of Invisibility, lent him by the wizards, must perform the mission alone.
This he does, battling not only the entranced Mouser, but enchanted skeletons and living statues, against which his weapons are all but useless. But he manages to escape and rescue Mouser, still mesmerized into thinking that the trash he sees is really valuable, including books of secret magics.