shield overload

I scrambled to my feet and held out my staff across my body, a slender barrier between me and the ghost on its home turf. "I guess it's too late to have a reasonable discussion, Agatha."
"My babies!" the spirit screamed. "Mine! Mine! Mine!"
"Yeah, that's what I thought," I breathed. I gathered my forces and started channeling them through the staff. The pale wood began glowing with a gold-and-orange light, spreading out before me in a quarter-dome shape.
The ghost screamed again and hurtled toward me. I stood fast and shouted, "Reflettum!" at the top of my lungs. The spirit impacted against my shield with all the momentum of a bull rhinoceros on steroids. I've stopped bullets and worse with that shield before, but that was on my home turf, in the real world. Here, the Nevernever, Agatha's ghost overloaded my shield, which detonated with a thunderous roar and sent me sprawling to the ground. Again.
I jammed my scorched staff into the ground and groaned to my feet. Blood stained my tingling fingers, the skin swelling with dark bruises and burst blood vessels.
Agatha stood several paces away, shaking with rage, or if I was lucky, with confusion. Bits of my shield-fire played over her shape and slowly winked out. I fumbled for my blasting rod, but my fingers had gone numb and I dropped it. I bent over to pick it up, swayed, and stood up again, red mist and sparkling dots swimming through my vision.
Michael circled the stunned spirit and arrived at my side. His expression was concerned, rather than frightened. "Easy, Harry, easy. Good Lord, man, are you all right?"
"I'll make it," I croaked. "There's good news and bad news."


Grave Peril Chapter 5, Page 41-42