Eight-year-old Prudence slips away from her family during a picnic, straying into nearby woodland just as the hot and humid day erupts into a terrible thunderstorm.
 
The air in the woods was thick and gloomy, a greenish night, stirred into a frenzy by the wind that now coursed like a wild thing through the canopy and between the trunks. Distantly, I could hear branches snap and fall. I peered into the dimness. The track disappeared into a throat of darkness.

Close by, a tree moved, separated itself from the shadows of the surrounding undergrowth and stepped towards me. I gasped and started backwards. I was not afraid because I’d been conjuring fantastical entities for as long as I could remember, but I was very startled—none of my imaginary figments had ever been as close as this. The figure was cloaked from head to foot in green—a Macintosh, a cape, a tarpaulin, I couldn’t tell. It was tall, towering over me, but also thickset and sturdy, very like the tree I had believed it to be. I couldn’t tell anything about it, it’s face shaded and shielded by its covering and the light in the woods so poor. It could have been a dryad like the ones in the Narnia books and I swear to God at that point I was so hopelessly disoriented that if Aslan himself had leapt over the gate I would not have been surprised.

The thing bent down and spoke to me, but its voice was low and cracked as though unused for eons. The noise in the woods was so loud, the storm shaking the canopy.  In spite of myself I yelled, ‘What?’

And then the storm broke right overhead. A rending of skies in a thunder crack that made my teeth rattle, and a simultaneous streak of lightning, as though heaven shone through the gap the thunder had opened. For that instant, the light was blinding—the interior of the forest lit up in silver and white—before the darkness returned, blacker and more otherworldly than before. The rain came, as though a bladder in the sky had been burst open, and the sound of that added to the cacophony, pebbles of water pounding onto leaves and slapping onto the ground forming instant rivulets and runnels that ran crazily across the woodland floor. Rain plastered my hair to my head. My clothes were instantly soaked. 

The figure croaked again, but it was just impossible to make out anything it said to me. It shook its head—irritated or resigned—and a gnarled old hand reached out from its coverings and took hold of my shoulder. I found myself turned from the gate and faced down the track, into the deep dimness of the woods where there was no light and where I did not recognise a single stick or stone or tree.