Young Macintosh didn't know what's going on. One moment, he was harvesting apples in the farm. The next moment, his hooves, his body, was on fire, and the orchard was burning with it.
But whereas the trees burned to ashes, he lived; the fires didn't touch him at all, for fire, as he discovered, it was his to command, an Element that reverberated deep within him.
He didn't know why, he didn't know how, and he would rather not have it. He mastered it, until fire could be controlled like an extension of his own body. but kept it a secret, from the rest of Ponyville, even from his own family.
But he knew, for good or ill, the day shall come when the fires must be released...