Striding down the street, an aged woman glances into each shop window in turn, dismissing each with a look of masked disdain. Finally she comes upon the one she had been seeking - a faded building, the lights off, the doors locked. She pulls from her vest a lockpick and brings it to the lock.
The lockpick melts due to the magical barrier. She gives the lock a scornful look, then picks up a heavy rock (with magical aid - it's far too heavy for her normally) and throws it at the window.
The rock bounces off and tumbles back to the ground.
The woman pulls out a pair of binoculars and peers through the window, trying to read the faint words left on the wall. Maybe she can at least see the prices, and the names of the goods sold.
No such luck. All the posters and signs have been covered up. The woman politely excuses herself from the situation, and waits until she's back in a wagon headed away from the city to curse the situation. Looks like Plan B won't work. Plan A has already failed her once, but maybe if she combs through the ashes she'll find what she's looking for.
Or at least, perhaps something that can point her in the right direction.