Battling For The Love of Bug-Types! (Japanese: ヒウンジム戦！純情ハートの虫ポケモンバトル！！ Castelia Gym Battle, the Pure-Hearted Bug Battle!) is the 25th episode of Pokémon: Black & White.
After the events of the last episode, Ash finally has his battle with Burgh at the Castelia Gym. Meanwhile, though the rest of their organization has pulled out of Unova, Jessie, James and Meowth remain there to do their best for Giovanni. James finds a Yamask and feeds it. After this act of kindness, Yamask is caught by James. During the Gym Battle, Ash's Sewaddle evolves into Swadloon and with it, Tepig and Pikachu, Ash wins the battle and the Insect Badge.
The heroes arrive at the Castelia Gym and remark it is like a big greenhouse. Burgh feeds a Sewaddle and notices the heroes. He jumps down, as Ash wants a Gym Battle. Burgh admits they moved the trees from Pinwheel Forest to the Gym, where the bugs enjoy the atmosphere of the Gym. Ash is excited to have the Gym battle, so Burgh snaps his fingers, which reveals a battlefield. Burgh sends Dwebble, while Iris notices how its rock looks different from the one of Cilan's Dwebble. Ash sends Tepig, who goes to tackle. Dwebble dodges and digs, hitting Tepig, continued by X-Scissor. Burgh tells Dwebble's rock is much lighter than those of other Dwebble, allowing it to move faster. Tepig uses Ember, though Dwebble protects itself.
Dwebble uses X-Scissor on Tepig, who tackles it back. Tepig uses Flame Charge, but gets countered by Dwebble's Protect. Using Rock Wrecker, Tepig is defeated. Ash calls Tepig back, while Cilan thinks Burgh lured Tepig in and defeated him with Rock Wrecker. Ash sends Sewaddle, displeasing Iris and Cilan for that choice. Burgh remembers Sewaddle, as his Leavanny made the cloak. Iris thinks Burgh is at an advantage, knowing Sewaddle, but Cilan tells he never saw it battle. Sewaddle uses Razor Leaf, but gets countered by Protect. Sewaddle uses X-Scissor, though Sewaddle uses String Shot to go up, dodging the attack. Sewaddle goes to use Bug Bite, though Dwebble protects itself and uses Rock Wrecker. Sewaddle uses String Shot to dodge and uses Razor Leaf, though Dwebble protects itself.
Dwebble uses Rock Wrecker, but Sewaddle uses String Shot to negate the attack. Sewaddle tackles Dwebble, countering its X-Scissor, causing Dwebble to lose its shell. Sewaddle uses Razor Leaf and tackles Dwebble. With Razor Leaf, Dwebble is defeated. Burgh calls Dwebble back and sends Whirlipede instead. Iris and Cilan see Whirlipede is a tough Pokémon, but Ash has no available Pokémon, being at a disadvantage. Whirlipede starts with Poison Sting, though Sewaddle uses String Shot to go up. It uses String Shot on Whirlipede, who rolls to cut the thread. Whirlipede uses Steamroller, hitting Sewaddle. It repeats the attack, negating Sewaddle's Razor Leaf. Sewaddle uses Bug Bite, though Whirlipede uses Iron Defense.
Whirlipede uses Steamroller and fires a Solarbeam. After the attack, Sewaddle evolves into Swadloon. Swadloon uses String Shot, but Whirlipede rolls, countering the move. Whirlipede uses Steamroller, so Swadloon uses String Shot to dodge. However, Whirlipede cuts the thread and uses Steamroller, but gets stopped by Swadloon's Energy Ball. Swadloon tackles Whirlipede, defeating it. Burgh calls Whirlipede back and sends Leavanny. Meanwhile, Team Rocket contact the HQ, though Giovanni's secretary replies. Team Rocket what their next assignment is, but the secretary replies it is up to them and logs out. Team Rocket is surprised, but see they need to go on their own missions, planning on catching Pikachu once and for all. Suddenly, a Woobat appears, so Jessie sends Woobat to catch it. However, James thinks it is hungry. After eating the food, Yamask joins Team Rocket, allowing itself to be caught by James.
Swadloon uses Energy Ball, but gets countered by Leavanny's Protect. Leavanny wraps Swadloon with String Shot, so Swadloon uses Razor Leaf on itself to free itself from the threads. Leavanny uses Leaf Storm, hitting Swadloon and defeats it with Hyper Beam. Ash calls Swadloon back and Oshawott comes out. Ash chooses Pikachu, shocking Oshawott, who is called back. Ash sends Pikachu, while Burgh admits one cannot expect what the challenger will send in the Gym Battle. Pikachu uses Thunderbolt, but misses and uses Iron Tail. Leavanny protects itself and uses Leaf Storm, while Pikachu collides using Thunderbolt. Levanny uses String Shot, wrapping Pikachu. Leavanny uses Leaf Storm, while Pikachu cannot use Quick Attack, as he is wrapped and gets hit.
Pikachu tries to break the thread. Leavanny uses Leaf Storm, attacking Pikachu, who uses Thunderbolt, but misses. Leavanny uses Hyper Beam, hitting Pikachu. It uses Leaf Storm, but Pikachu rolls, allowing the attack to cut the threads and Pikachu is freed. Leavanny uses String Shot, though Pikachu avoids it with Quick Attack and counters it with Thunderbolt. Using Iron Tail and Electro Ball, Pikachu defeats Leavanny. Burgh comes to Ash and gives him the Insect Badge and adds it to the case. Later, the heroes bid farewell to Burgh, as they continue onwards.
- This episode had some elements similar to "Gettin' the Bugs Out".
- The Gyms are shaped as greenhouses.
- Burgh encountered the heroes in his Gym on a tree, similar to Bugsy.
- Ash used Pikachu, a Fire-type Starter Pokémon (Cyndaquil) and a Grass-type Pokémon (Chikorita).
- Bugsy's Spinarak, like Ash's Swadloon, used String Shot to move and dodge attacks.
- This episode was supposed to air two weeks later but was bumped after the episode "Team Rocket vs. Team Plasma" delayment.
- The music motto of Team Rocket in the Diamond & Pearl series is back and added to the Black & White series.
- Like Cacnea, James befriended Yamask to catch it.
- Professor Oak's Live Caster: Herdier
- The "Who's That Pokémon?" is Leavanny.
In the English Dub, Giovanni's secretary says he's busy with meetings and cannot be bothered to give Jessie, James and Meowth a mission; she says what they do from then as their mission is up to them. This is due to the previous two episodes not being aired.