While enjoying a festival after winning a big promotional contest in Alamos Town, Joeshur Riverside and his Pokémon gal-pal for life Nian suddenly get caught in a dispute between two legendary Pokémon, plunging Alamos Town into the throes of chaos and destruction.

Unfortunately, while directing his Mega Lopunny to protect the civilians and other Pokémon caught in the wake of the legendaries' cataclysmic battle by deflecting any wayward attacks, the two close friends are then blasted by the legendary Pokémon, sending them hurling into a portal seemingly created by their clash.

After recovering with no injuries to speak of, Joeshur and Nian find themselves on a plain unfamiliar to them. Unbeknownst to the duo, they were sent to another world.