In Lively Town on the Water Continent, a team of Froakie and Riolu rush to their first day of work at the Expedition Society. Ampharos assigns them to explore the newly-found dungeon CoroCoro Pass, though warns the team of a strong Pokémon reported to be deep inside it. In light of this, Archen is assigned to assist them on the mission.

As the team reaches the dungeon's depths, Riolu recalls Ampharos's advice, and the team is suddenly attacked by a territorial Garchomp, who approaches from above and declares them intruders.