"I don't know," muttered a fire-type, her flames dimming as she gazed out over the wall. "It's like something's pushing them back."
Then, to the amazement of all present, the temperature plummeted.
The oppressive heat that had clung to the base for weeks disappeared, replaced by a sudden chill.
A cool breeze swept through the area, brushing against their skin like a refreshing wind in the midst of summer.
The change was so abrupt, so palpable, that many of the citizens stared at each other, stunned.
"It's freezing all of a sudden," one defender muttered, rubbing his arms as goosebumps rose along his skin.
"But… why?"
The invisible forcefield surrounding the base became faintly visible, not as a solid wall but as a shimmering distortion in the air, like heat waves bending the light.
The citizens could sense its presence now, the subtle but unmistakable barrier keeping the zombies at bay.