Yes! Plugging it in did bring everything back to light, except that when plugged in, it only let me adjust the brightness level when running on plugged-in power, not when on battery power. The moment I disconnected the power, the screen went dark again.

However, it didn't take my pea brain long to figure out that I should just position my stylus in the appropriate spot when the screen was on and plugged in, and when I pulled out the plug, I simply dragged the stylus across the dark screen and up came the brightness!

Thanks to all for such quick replies.

Anthony in Chicago

BTW, I even took the device into a windowless room with no lights, and there is simply no visible display when the brightness is turned all the way down. I even waited for my eyes to adjust to the darkness. I truly don't understand why they would let it go this far.