Ash and friends have delivered the GS Ball safely to Kurt and are heading to the Azalea Town Gym for the next badge. Misty thinks Ash will have a tough time with without Charizard but Ash is confident that Cyndaquil has the firepower he needs.
The Azalea Gym is a large dome with a forest-like environment inside. Misty becomes nervous, then a Caterpie drops down in front of her and she freaks. A boy standing up on a tree branch says that this is in fact the Gym and that bug Pokemon are the best. Misty isn't thrilled. Ash introduces himself and the boy says he's Bugsy, the Gym leader. Bug Pokemon are his specialty.
Team Rocket is watching, decide to grab Pikachu while Ash is distracted by his match. They go into the gym disguised as a flower, tree and clump of weeds, but they are noticed by a number of bug Pokemon who tie them up with their silk. This match is a three-on-three battle. Bugsy begins with a Spinarak and Ash brings out Cyndaquil. It looks tired but Ash thinks it'll get warmed up soon enough. Spinarak uses a series of String Shots which Cyndaquil dodges, but then Bugsy has it cover the whole field and Cyndaquil eventually gets caught. Ash has it try to use Flamethrower but it's not warmed up enough yet. Spinarak uses Poison Sting and Cyndaquil is hurt, forcing Ash to recall it. Brock is concerned, because Cyndaquil is the only Pokemon Ash has that's strong against bug types. Ash takes a gamble with Chikorita, which surprises Bugsy. Chikorita dodges Spinarak's attacks easily and retaliates with Vine Whip but the Spinarak begins to swing around from the trees on a silk line, and it's difficult to hit. Ash tells Chikorita to use its Sweet Smell and the Spinarak gets paralyzed, giving Chikorita the chance to Tackle it and knock it out. Chikorita is very happy, this is its first Gym win.
TR is watching again (they got out of the cocoon somehow) and plan to dig under the arena and grab Pikachu from beneath. For the second round, Bugsy brings out a Metapod. Chikorita uses Vine Whip and Razor Leaf but Metapod Hardens which renders the attacks ineffective. Then in a surprising move, Metapod hops up into the air and tackles Chikorita to win. Ash recalls Chikorita and sends in Pikachu.
Metapod Tackles Pikachu, stirring up a cloud of dust so Pikachu can't see it. However, Pikachu can still hear it, and dodges its attacks. Pikachu uses Agility to get close enough, then jumps onto Metapod and Thunders it to knock it out. Bugsy congratulates Ash, he's the first person in a long time to last until the third round. But Bugsy has saved his best Pokemon for last: a Scyther. TR is underground, listening. The movement above has stopped, so it must be time to dig up. James pokes his head out right behind where Scyther is standing, just as Pikachu uses a Thunderbolt! All of them get shocked and they fall back into their tunnel.
Scyther does multiple Slash attacks which Pikachu is unable to avoid and gets knocked out. Ash brings out Cyndaquil again, and it dodges Scyther's attacks until its flame finally lights. Scyther's Double Team move only serves to make the flame burn brighter. Now Ash tells it to use Flamethrower but Scyther performs a Swords Dance and spins, and the fire is spread away from it. Bugsy says he and Scyther have developed counter moves to all the fire-based attacks.
Ash isn't giving up. He anticipates Scyther's next move, tells Cyndaquil to leap overhead and blast Scyther from above with Flamethrower. The Scyther is greatly weakened, and Cyndaquil uses a Tackle to finish it. Bugsy is impressed, and awards Ash a Hive Badge for the victory. He and Ash agree to have a rematch the next time Ash passes through town.
The friends plan to depart. Kurt's granddaughter catches up to them and gives them new PokeBalls: Lure Balls for Ash and Misty, a Heavy Ball for Brock. She says her grandfather is still working on the GS ball, and they are all welcome to come back and visit on their way back to Pallet Town. That night, Team Rocket is still trapped in their hole under the Gym, surrounded by lots of bug Pokemon.