Written: http://psycoti.ca/0/main/aging_magic.html

General image of a person staring in awe as a wizard or something stands before a huge cloud of fire, redirecting it, and generally doing awesome battle.

Cut to same kid, older, with aging old frail and crazy person.

The guy is looking after his old mentor and generally frustrated at his inability. As the guy is leaving, the old one says something like "Remember that time with the fire" and the guy says, tiredly, "Yes, I remember", but then, as he's leaving, more sincerly, "I'll always remember"

I like the juxtaposition of the power of a person in their prime, with the inevitibility of weakening later.