An explosion occurs as a rare Pokémon Riolu is stolen from a laboratory. The group of men that stole Riolu is discussing about how Riolu is a fool for trusting them. Riolu overhears the group talking about how they tricked it. It gets mad and busts its way out of the truck and escapes.

Ash and co. are continuing their way through the Sinnoh region. They suddenly come across the Riolu, who is injured. Ash tries to help it, but Riolu fights back with Aura Sphere, an attack that is usually learned by Lucario. A boy in a green coat suddenly appears, and Riolu runs away. Ash wants to go after it, but the boy tells him that he will handle it. The group hides behind a bush, as they watch Riolu sitting on a tree branch. The boy says that Riolu just wants to go back to its home.

Suddenly, Pokémon Hunter J's henchmen appears. They have come to capture Riolu. A Crobat is sent out, and it attacks Riolu. Pikachu attacks Crobat back with Thunderbolt. The henchmen are getting frustrated, so they send out more Crobat. The boy reveals himself as a Pokémon Ranger. Using his styler, he captures an Ariados and Nincada to defeat the henchmen. Then the boy presents Riolu with a wooden figure of itself, a token that must be important to Riolu. It is a way to get Riolu to trust him.

The boy introduces himself as Kellen, and he takes Riolu to a safe place. Kellen knows that it will take some time for Riolu to trust people again, since it's been through some tough times. Riolu stares at the doll that Kellen gave to it. Ash realizes that the doll is very important to Riolu, since it was able to see its memories through its aura. Pokémon Ranger Solana calls Kellen about the latest update on the search. She reports that they found the location of Hunter J's client, and she and Officer Jenny are headed there now.

Hunter J's ship finally arrives, and Ash and co. know that she plans on taking Riolu. So Ash and co. decides to take a boat out into the lake. Kellen explains the whole story about Riolu to Ash and co. and how it ended up being the target of so many criminals. His mission is to transport Riolu back to its home safely, and so they are headed towards headquarters where that will happen.

Suddenly, four Sharpedo burst out from underneath the water and destroys the boat. The Sharpedo belong to Hunter J. Kellen captures a Floatzel, and the group begins to swim away. The Sharpedo attacks Ash and co. with Aqua Jet, but Pikachu manages to shock them down. Suddenly, Hunter J herself appears on her Salamence. She fires her gun at Riolu but misses. However, the explosion causes Riolu to lose its doll. Riolu chases after it, and Ash follows it.

The current is too much for Riolu, and it sinks underwater. Ash and Buizel dive underwater, and they rescue Riolu. When Riolu wakens from its sleep, Ash gives the doll back to Riolu. Meanwhile, Hunter J and her henchmen are discussing where Riolu might be hiding. They find Ash and Riolu running through the forest, and Hunter J comes up with a plan. She uses her Salamence to create a huge wildfire in the forest. The Fire Blast from Salamence blocks Ash's escape. Ash refuses to give Riolu to Hunter J, so she commands Salamence to use Flamethrower. Will Ash be able to escape Hunter J and return back Riolu safely back to its home?

English Official Summary

In the middle of the night, chaos breaks loose in an isolated research center as research subject RX-1, a Riolu, escapes with the help of several men and a getaway truck. But the men want to steal Riolu, not help it, so Riolu breaks out again and flees into the forest. The next day, nursing an injury, it encounters Ash and the gang, but mistakes them for more false friends and blasts Ash with Aura Sphere when he tries to help. Fortunately Kellyn, a Top Ranger from the Pokémon Rangers, catches up with Riolu. Kellyn is just in time to stop Pokémon Hunter J's minions from grabbing Riolu themselves; he uses his Vatonage Styler to recruit nearby Bug Pokémon to halt the thugs' kidnap attempt. Now that everyone can relax, he explains that Riolu hails from the Paradise Kingdom, where it uses its special Aura powers to serve as the kingdom's guardian. Those powers strike a chord with Ash, who's able to sense mental images of Riolu's past. Riolu was kidnapped from its kingdom and is now on Pokémon Hunter J's target list, so Kellyn, together with Pokémon Ranger Solana and Officer Jenny, is here to save Riolu and get it back home. As proof of his good intentions, he brings Riolu a wooden carving made by the old man who raised it. Hoping to evade Pokémon Hunter J, Kellyn teams up with our heroes to escort Riolu downriver toward a waiting recovery team. It's all for naught, though, as Pokémon Hunter J and her Salamence attack, forcing everyone to scatter. Ash manages to rescue Riolu and its prized carving from the water, but they wind up lost on a riverbank and cut off from the others, with Pokémon Hunter J's goons already searching the forest around them. Ash and Riolu make a break for it, only to be spotted. Pokémon Hunter J coolly decides to flush them out into the open by burning down the forest around them, and Ash and Riolu escape the flames only to find themselves cornered by J and her Salamence. Are Ash and Riolu ever going to get out of this in one piece...?

French Official Summary

Sacha et ses amis croisent le Pokémon Ranger Primo, chargé de retrouver Riolu, de le protéger et de le ramener chez lui.

German Official Summary

Unsere Helden lernen Pokémon Ranger Primo kennen, der ein ganz besonderes Riolu in sein Zuhause zurückbringen will.

Italian Official Summary

Nel cuore della notte in un isolato centro di ricerca si scatena il caos improvviso, quando il soggetto sotto osservazione RX-1, un Riolu, fugge con l'aiuto di alcuni uomini e di un furgoncino.

Portuguese Official Summary

Nossos heróis conhecem o Patrulheiro Pokémon Kellyn que está em missão para retornar um Riolu muito especial ao seu lar.

Finnish Official Summary

Sankarimme tapaavat Pokémon-ranger Kellyn, jonka tehtävä on auttaa erikoinen Riolu takaisin kotiinsa.

Spanish Latin America Official Summary

Nuestros héroes conocen al Pokémon Ranger Kellyn, que está en una misión para ayudar a un Riolu muy especial a regresar a casa.

Spanish Official Summary

En medio de la noche, el caos se desata en un centro de investigación aislado. El sujeto de investigación RX-1, un Riolu, se escapa con la ayuda de varios hombres y un camión para la huida.

English Great Britian Official Summary

In the middle of the night, chaos breaks loose in an isolated research center as research subject RX-1, a Riolu, escapes with the help of several men and a getaway truck. But the men want to steal Riolu, not help it, so Riolu breaks out again and flees into the forest. The next day, nursing an injury, it encounters Ash and the gang, but mistakes them for more false friends and blasts Ash with Aura Sphere when he tries to help. Fortunately Kellyn, a Top Ranger from the Pokémon Rangers, catches up with Riolu. Kellyn is just in time to stop Pokémon Hunter J's minions from grabbing Riolu themselves; he uses his Vatonage Styler to recruit nearby Bug Pokémon to halt the thugs' kidnap attempt. Now that everyone can relax, he explains that Riolu hails from the Paradise Kingdom, where it uses its special Aura powers to serve as the kingdom's guardian. Those powers strike a chord with Ash, who's able to sense mental images of Riolu's past. Riolu was kidnapped from its kingdom and is now on Pokémon Hunter J's target list, so Kellyn, together with Pokémon Ranger Solana and Officer Jenny, is here to save Riolu and get it back home. As proof of his good intentions, he brings Riolu a wooden carving made by the old man who raised it. Hoping to evade Pokémon Hunter J, Kellyn teams up with our heroes to escort Riolu downriver toward a waiting recovery team. It's all for naught, though, as Pokémon Hunter J and her Salamence attack, forcing everyone to scatter. Ash manages to rescue Riolu and its prized carving from the water, but they wind up lost on a riverbank and cut off from the others, with Pokémon Hunter J's goons already searching the forest around them. Ash and Riolu make a break for it, only to be spotted. Pokémon Hunter J coolly decides to flush them out into the open by burning down the forest around them, and Ash and Riolu escape the flames only to find themselves cornered by J and her Salamence. Are Ash and Riolu ever going to get out of this in one piece...?

Russian Official Summary

Среди ночи изолированный исследовательский центр погрузился в хаос, когда предмет исследований, Риолу, сбежал на грузовике с помощью нескольких неизвестных.

Dutch Official Summary

Midden in de nacht breekt er chaos uit in een afgelegen onderzoekscentrum wanneer RX-1, een Riolu die daar is voor proeven, geholpen door enkele mannen ontsnapt in een vrachtwagen.

Norwegian Official Summary

Våre helter møter Pokémon Ranger Kellyn, som har et mål om å få en veldig spesiell Riolu tilbake til hjemmet sitt.

Swedish Official Summary

Våra hjältar träffar Pokémon-rangern Kellyn, som har som uppdrag att hjälpa en mycket speciell Riolu att återvända till sitt hem.

Danish Official Summary

Vore helte møder Pokémon-rangeren Kellyn, som er på en mission for at hjælpe en meget speciel Riolu med at vende hjem.