Harley Rides Again (Japanese: ゴンベのデビュー戦！ハーリーと真剣勝負！！Gonbe's Debut Battle! Harley and Taking the Game Seriously!!) is the 160th episode of the Advanced Generation series, and the 434th episode of the Pokémon anime. It first aired in Japan on January 19, 2006 and in the United States on October 28, 2006.
May is preparing for the Pokémon Contest in Wisteria Town when her old rival Harley shows up and vows to beat her. He's even got one more Ribbon than she does! Harley also runs into Team Rocket, who offer to help him beat May if he'll help them steal Pikachu. Harley just laughs and laughs at the idea, infuriating Jessie.
May starts the Contest with a dazzling display from Squirtle, and Harley brings out Ariados for an impressive but scary show. During the appeal, Wobbuffet suddenly falls onto the stage, then runs away. As May and Harley move on to the next round, Pikachu and Ash investigate this odd occurrence. Chasing after Wobbuffet, they find Team Rocket busy stealing Pokémon—Wobbuffet fell onto the stage because it fell out of their balloon. Team Rocket tries to convince Ash they're really big May fans, but Pikachu quickly sends them packing.
Harley and May make it to the Contest finals, and Harley's brought his Octillery. Moves like Constrict and Octozooka hit hard, but Munchlax strikes back with Metronome. Harley has Octillery use Rest to restore its health, so now Munchlax must knock it out before it wakes up! But at the last minute, Octillery wakes up and defeats Munchlax with Octazooka. May's not too upset about her loss, though. She has her next Pokémon Contest to look forward to—and a message from an anonymous admirer. Could it be Drew...
Ash and his friends finally arrive in Wisteria Town, where May will compete in the Wisteria Contest to try to win her third Ribbon. She practices with her Munchlax by throwing a ball into the air and having Munchlax use Focus Punch to break it, dropping confetti everywhere. May is impressed by the powerful yet cute display, adding that she is confident she will win her third Ribbon. Eevee indicates that it wants to be in the Contest, but May tells it they need more practice first. Ash asks May if she has decided whether to use Munchlax in both rounds or not. May says she will go with Squirtle in the Appeals round and Munchlax in the battle round. Everyone’s attention turns to Brock, who is surprising surrounded by a group of girls, though they are admiring his adorable Bonsly. Harley appears, scaring off the female entourage, and hastily approaches May to declare that he will defeat her. May fires back, showing off her two Ribbons, though Harley admits his three are much better. The two rivals exchange a final word before Harley walks off to continue his preparations. May is left feeling agitated, though her friends advise her to keep cool and focused on the Contest.
Harley soon encounters Team Rocket at their Pokéblock stand. He isn’t interested in their wares, but the trio get his attention with the offer of secretive information. Team Rocket offer to help Harley beat May in the Contest if he would help them capture Pikachu. He recognizes them as Team Rocket, the bad guys who are always defeated badly by Ash and his friends. Harley laughs hysterically, calling them complete and total losers, and saying he would become a total loser like them if he tried to use any of their help. As Harley leaves, Team Rocket become embarrassed and enraged by his public insults and vow to show him not to mess with them.
At the Contest Hall, Brock tells Eevee to watch May closely as she shows how great Pokémon Contests really are and what they are about. Lilian introduces the panel of judges, formed by the Chief of the Pokémon Activities Committee, Raoul Contesta; the President of the Pokémon Fan Club, Mr. Sukizo; and Wisteria Town's very own Nurse Joy. May brings out her Squirtle for the Appeals round. Squirtle enters into a Rapid Spin before using a Bubble attack for twirling combination. Squirtle uses Ice Beam to break the bubbles, covering the stage in ice before finishing up with another Ice Beam for a frozen fountain spray effect. The audience applauds the icy spectacular as Squirtle and May hold their finishing poses.
Harley takes the stage and brings out his Ariados, who appears with its back to the audience. Ariados covers the stage in Spider Web threads and starts climbing and crawling around on it. Ariados bungee jumps from the top with the string attached to its abdomen. It spins itself around while wrapping itself with string and uses Scary Face to scare everyone. Before finishing off its last move, a Wobbuffet falls from the ceiling and crashes onto the ground. Ariados uses Scary Face to frighten Wobbuffet, sending him running scared. Pikachu immediately senses something is up, and runs outside the Contest Hall with Ash in pursuit. The results of the Appeals round are in, and May is in first place with Harley in second. Backstage, Harley is unimpressed and tells May she won't be in the lead for long. May assures Harley that she is on her way to winning the whole thing.
The first battle of the Battle Round begins. May's Munchlax goes up against her opponent's Politoed. Munchlax charges up its Solar Beam and fires just before Politoed's Water Gun. Solar Beam takes out Politoed in one hit, allowing May to move on to the next round easily. Meanwhile, Team Rocket are using one of their machines to grab Coordinators' Pokémon, leaving the Coordinators with no idea where they went. Wobbuffet returns to them, but Pikachu and Ash have followed him to the roof. Ash demands to know what they are up to, and Team Rocket claims to be trying to help May win. Ash interrogates them about the stolen Pokémon, which Team Rocket claim is their commission for helping May. Ash doesn't believe them and has Pikachu use Thunderbolt to blast them away. Later, Lillian announces May and Harley as the two Coordinators who will face off in the final round.
Before the match, Lillian says to everyone that because Harley and May have won in the past, this Contest Battle will be of a high level. Harley brings out Octillery while May releases Munchlax. Munchlax uses Focus Punch and Octillery jumps high in the air, lands on top of Munchlax, and uses Constrict. Munchlax tries to use Focus Punch to knock Octillery off of it, but it fails and Octillery uses a powerful Octazooka at point-blank. Munchlax uses Solar Beam, but Octillery's Sludge Bomb hits first and causes an explosion. Near the end of her rope, May takes a risk and has Munchlax use Metronome, which at first appears to do nothing. Harley and Octillery begin to laugh at the failed move, but suddenly a powerful Thunder drops down onto Octillery. Even after this lucky break, May is still way behind on remaining points. Octillery uses Rest to fully heal, alarming May's friends, who urge her to attack before Octillery wakes up at full health. Munchlax uses Tackle, Focus Punch, and another Tackle, which put a dint into Harley's points but it isn't enough to defeat Octillery. Octillery awakens and knocks Munchlax out with a direct flash of Octazooka. Harley is declared the winner and acknowledges the crowd after being handed his fourth Ribbon.
Later that day, May rewards Munchlax with a well-deserved feed and the boys assure May that she did a great job during the Contest. Meanwhile, Harley says to himself that nice girls finish last. Lillian comes up to May and hands her a flier about the next Contest which will be held on Chrysanthemum Island. Lillian also hands her an envelope and a rose from an unknown sender, who Brock deduces to be Drew. May opens up the envelope and reads the letter. The sender says that he or she looks forward to seeing her at the Chrysanthemum Contest.