Pokémon XY: The Strongest Mega Evolution (Act 4) - S0.E45

Alain has returned to Kalos with Lysandre to be tested in a match against ten Mega Evolved Pokémon. Alain loses his Mega Stone and Key Stone if he fails. Meanwhile, Chespin discovers scientists performing experiments on an unknown Pokémon, which leads it to fall victim to a mysterious illness.