Pokemon XY: Mega Evolution

Mega Evolution": A new form of evolution first introduced in the Kalos region. However, is mega evolution something all Pokémon are capable of? This story is centered around a young Trainer named Alan and his partner Lizardon. "To master Mega Evolution, to defeat all mega evolved Pokémon and stand on top as the strongest": That is the goa of Alan's journey. As they travel around, Alan and Lizardon engage in a Mega Evolution Battle against a Mega Absol and a Mega Gablias. And then, they battle Zumi of the Elite Four. Does Zumi have a mega evolved Pokémon as well...? Why is Alan so obsessed with Mega Evolution? And what is the true purpose of Alan's journey?