On their way to Lake Valor for the Grand Festival, Ash and his Gang stop off for a break. Upstream, a Pokémon Ranger is attempting to capture a Heatran. Nearly captured, it flees before the capture is complete with the Ranger falling in the river. Saved by a Feraligatr, he greets Ash and company and introduces himself as Ben. He asks for their help in capturing the Legendary Pokémon and they agree. The feat will not be as simple as he wishes, for Team Rocket has also set their sights on the Lava Dome Pokémon. Will Ben and his new friends capture the fiery Pokémon and save it from harm or will Team Rocket finally get their clutches on a powerful legend?