Lost Leader Strategy! (Japanese: ルカリオ！怒りのはどうだん！！ Lucario and the Aura Sphere of Rage!) is the 14th episode of Pokémon: DP Battle Dimension.
Ash and friends arrive in Veilstone City where they meet Reggie who is not only Paul's older brother but a top Trainer who had accomplished as much as Ash did expect for one thing. They also meet Maylene, the Veilstone Gym Leader who apparently has some confidence issues after losing to Paul. She just hasn't been the same, so much that she decides to quit. Dawn has a talk with her and relates as she has lost two contests in a row and has taken a break. Will Maylene be able to get back what she lost? Can Ash be able to beat Reggie in a Pokémon battle? And Why would Dawn request a Gym Battle?
The heroes came to Veilstone City, where Ash will challenge the Gym Leader. Suddenly, some balls are being launched and Ash recognizes them to be Aura Spheres. The heroes run and see a woman training with a Lucario. They see it is very powerful, though they train intensively. Suddenly, they get attacked by a Thunderbolt and see it is an Electabuzz. Piplup and Pikachu seem to be very offended by its presence, even attacking it. The heroes try to stop them, but get electrocuted. This causes a break from the woman's and Lucario's training. With an Aura Sphere, Lucario stops them.
A man comes and demands to know why Electabuzz attacked. Pikachu confirms Ash's guess Electabuzz is Paul's. The man hears this and introduces himself as Reggie, Paul's brother. Ash introduces himself as the one to challenge the Gym Leader, so Reggie points at the woman, who is the Gym Leader. Her name is Maylene, though she wants a break, but this causes her to be attacked by Lucario, as it is not too happy with her being its trainer, while Team Rocket sees all this. Men, who are black belts, come to warn Maylene to come back to the Gym. Maylene does not want to, as she does not want to be a Gym Leader anymore, even reflecting Lucario's Aura Sphere. Reggie knows it must be because of Paul, as he used Pokémon that had advantage - Honchkrow (which evolved from Murkrow) defeated two of her Pokémon and Lucario was defeated by Magmar, which he recently caught.
Maylene now feels bad for the defeat, knowing that it was not worth to call a Gym fight. When he got the badge, Paul confessed that was the easiest fight yet and called her a weak leader. Maylene accepted this and runs away. Reggie and Lucario promise to take care of this. Ash admits it would be good to fight Lucario, at least, so Brock proposes to go to a next Gym. Dawn stops them and goes with Lucario to find Maylene, to have a discussion with her. While Dawn and Lucario go talk to her, Reggie tells about Maylene - she was a famous trainer and was promoted to Gym leader, but she now has doubts about all this. Dawn tells Maylene that she is taking a break from the Contests, but it is for getting prepared for next. Maylene confesses it is hard to fight as a gym leader and is still in doubt about Paul's words, though Dawn tells that Paul is like that all the time.
Maylene and Dawn are unsure what to do next. Team Rocket appears behind them, as they want to get Lucario for someone better, unlike the "Gym loser". Reggie would like to know how Ash copes with Paul's strategies, but Ash does not know how to deal with them, as he should bond with Pokémon. Reggie would like to see that. Meanwhile, Team Rocket offers many gifts to Lucario, but this causes them to blast off. Dawn knows that even if Lucario is still angry at Maylene, it still cares for her. Dawn proposes a battle between them, while Reggie with Ash. Ash accepts the challenge and goes to prepare himself. Reggie notices Chimchar has grown better, while Brock notices the Gym Badges, including Frontier Symbols. They go out to battle.
Dawn and Maylene come and go to see the battle. Ash sends Gligar, but to see the battle. Ash sends Turtwig and Reggie Bibarel. Turtwig uses Energy Ball, but Bibarel uses Super Fang to cancel the move. Bibarel uses Secret Power and puts Turtwig to sleep. Bibarel charges using Take Down and hits Turtwig, who wakes up. Bibarel uses Super Fang, but misses and gets hit by Razor Leaf. Turtwig uses Energy Ball, evading Bibarel's Ice Beam and defeating it. Maylene is fascinated and Dawn explains Ash really trained and raised Turtwig well. Reggie sends Swalot and sends Staravia. Staravia hits Swalot using Wing Attack, but uses Stockpile. This repeats again. Staravia charges with Aerial Ace, but Swalot counters and launches all its stored energy. Staravia uses Aerial Ace once more, but gets hit by Sludge Bomb. Ash gets Staravia before it fell. Reggie would like to train Staravia to use a move, but not before the end of the battle.
Reggie sends Staraptor and Ash his Pikachu. Pikachu uses Thunderbolt, but misses and retaliates with Brave Bird. Pikachu spins to dodge, but fails and gets hit by the move. Staraptor uses Steel Wing, but Pikachu bounces off using Iron Tail, then uses Volt Tackle. Staraptor uses Wing Attack. Though Pikachu is hurt, Staraptor is defeated. Ash thinks Reggie thought of Brave Bird when he told what move he is going to teach. Reggie confirms this and knows Staravia will learn it quickly, seeing the Aerial Ace. Reggie asks Maylene if she wants to accept Ash's challenge, but Dawn stops them, as she asked first!
Rachael Lillis returned to voice Maylene.
While Dawn is talking to Maylene near a river, Lucario is seen behind her in one scene, and in the next frame he is gone. After that, Lucario reappears behind Maylene.