MissiNg (Pokémon)

Lestia is about to start her Pokémon journey, when she bumps into N, and he has an urgent plea for her: Help him find the Legendary Hero Ayla who has gone missing. She agrees to help N, and he hugs her in thanks, when Lestia sees one of Ayla's old memories. How can this memory help the duo on their journey to find Ayla?