Smolder showed them the Jaguar's Eye/Explaining the whole story

Here is how Smolder Bravestone explained the whole story in Princess Yuna and Jumanji.

As for Luna and Hiro, they were starting to worry about Yuna and her friends inside Jumanji.

Princess Luna: I'm worried about Yuna and Snowdrop.

Hiro: They're very brave, Luna. And if anypony can keep it's good friends together in one piece, it's Yuna.