The fire spread quickly through the bushlands, consuming dry trees and old tinder with ferocious force and intensity. The firefighter mystics did their best to arrest the spreading flames, using their most potent charms and spells. Some of the senior wizards managed to set up a floating bucket line, but they kept having to adjust the enchantments to direct it to more urgent areas of the blaze.
Eventually the wizards succeeded in bringing the fire under control, and the villagers were able to go and inspect the damage. Only the edge of the village had been touched - the one by the school. In fact, it looked as if the fire had started from nothing in the woods, in many places at once, and spread only as far inwards as the school's kitchen.
Investigating the kitchen itself was clearly going to be a difficult task. Pots and pans had melted from their holding hooks on the ceiling, the stone bench tops had cracked and shattered, and everything else was charred to ruin.
The embarrassed school cook shuffled awkwardly to the back of the gawking crowd, trying not to be noticed as she went. It had only been a small spell, meant to get the cooking done faster so she could get back to her reading. She wasn't much of a sorceress herself, but for goodness' sakes, the children did this kind of thing all the time!
She had figured out what went wrong about the time the school had been evacuated. The spell started a fire that moved backwards in time, approaching the kitchen and getting hotter as it went, eventually stopping there, or looking like it had. Should she confess? Well, the wizards would find out the truth eventually, and it might as well be via confession rather than investigation. After the cleanup had started in earnest, and the investigation began, she came forward to tell her tale and, if necessary, accept her punishment.
Mokalus of Borg
PS - I suppose there's a bit of Harry Potter in this.
PPS - With a bit of the Australian outback, too.