Riolu, Pikachu and others in “Caring for a Mystery!”

Riolu! Olu! Olu! Olu! [I want to join your team to better myself!]

Pikachu

Pika? [You sure?]

Riolu! [I am!]

It looks to me like Riolu is trying to tell you something.

Huh?

I think it wants you to catch it!

Huh? You sure you want that?

Olu! Olu! Olu! [Yes! Go for it!]

Here goes! [whips out a Pokéball and finally catches Riolu. Fans are finally satisfied that Ash now owns a Riolu.]