The Fires of a Red-Hot Reunion! (Japanese: 燃えよリザードン！VSカイリュー！ Hepburn: Burn, Charizard! VS Dragonite!) is the 19th episode of Pokémon: BW Adventures in Unova and Beyond.
Heading towards the White Ruins, Ash and co. come across a special Kanto Fair, a fair celebrating the region of Kanto and the various Pokémon that dwell there. Ash is excited to see all these attractions that remind him of home and ends up seeing a cheerful Charmander right on stage. Reminding him of his old friend after telling his stories to them, Ash calls Professor Oak and requests that he sends over Charizard (since he came back from Charific Valley) while he sends Unfezant to his lab. However, once there, Charizard soon meets Iris' Dragonite and a fierce rivalry between them begins with a battle. Will the battle last? Who will win?
The heroes visit a festival dedicated to the Kanto Region. Ash already recognizes some Pokémon, like Squirtle, Charmander, and Bulbasaur. Ash decides to check out this festival, with his friends following him. Passing by a trader wanting to sell Magikarp, the heroes soon see Prof. Oak on the screen, who introduces Squirtle, Bulbasaur and Charmander, the Kanto Starter Pokémon. N asks which Pokémon Ash chose. Iris replies that he chose Pikachu, so Ash explains to N that Pikachu was the only Pokémon left, since he overslept on that day. Cilan calls this fate. Prof. Oak logs out, while the announcer decides to show some Kanto region Pokémon. N admits it's his first time seeing such Pokémon.
The announcer shows a Charmander, who walks to the stage and spins around, showing its happiness. Iris admits Charmander's cute, but free-spirited. Charmander spins around and uses Ember, but becomes dizzy and starts wrecking the stage. Later, Nurse Joy heals Charmander, while the announcer replies that Charmander got excited in front of an audience. The heroes ask how Charmander is doing, and Nurse Joy replies it'll be fine soon. Later, Ash admits he was thinking when he caught his own Charmander. Ash still remembers how Charmander's original trainer had abandoned it, claiming it was too weak, and he, Brock and Misty had to rescue Charmander and rush it to the Pokémon Center before its tail flame went out. N is certain that the trainer did not want to return to pick Charmander up. The next day, after Charmander was healed and burned Team Rocket with its newly learned Flamethrower attack, his original trainer, Damien showed up. Damien tried to recapture Charmander, but the Lizard Pokémon had seen his old trainer's true colors and refused to go with him. Ash then welcomed Charmander into his team.
Charmander fought well against Primeape (who took Ash's hat) and Koga's Golbat, winning Ash the Soul Badge. Also, when they were stuck in a snowy cave, and Charmander, along with Bulbasaur, Pidgeotto, Squirtle, and Pikachu, shared their warmth with their trainer. Eventually, Charmeleon evolved, but also started disobeying Ash. Cilan states that when a Pokémon evolves, sometimes its personality changes as well. Ash still battled with Charmeleon and when he was kidnapped by an Aerodactyl, who taunted Charmeleon, it evolved into a Charizard. They still went to the top, for Charizard battled Blaine's Magmar and won. Unfortunately, at the Indigo Plateau, Charizard refused to attack Sparky and cost Ash the victory. Iris thinks Charizard was a pain, but Cilan reminds her that she had the same problem with Excadrill and Dragonite.
Everything changed when Charizard fought against Tad's Poliwrath. Poliwrath defeated Charizard by dousing its tail flame and then encasing it in ice. Ash spent that night warming up Charizard and telling it how they will keep getting stronger together. The next day, Charizard recovered and started obeying Ash from that moment on. Cilan is surprised that Ash isn't traveling with such a powerful Pokémon. Ash admits that Charizard is training at the Charicific Valley. After becoming so powerful, it won every battle, but encountered lots of other Charizard and was defeated by all of them. Ash left Charizard there, knowing it would get much stronger by training there. Eventually, Ash used Charizard to battle Clair's Dragonair and won the Rising Badge, the battle against Gary and his Blastoise, even Noland's Articuno for the Knowledge Symbol.
Ash is certain that Charizard is still in training. The announcer of the festival comes in and apologizes for the trouble. Charmander is okay, so Ash pats Charmander, asking it to be careful. Iris and Cilan want to meet Charizard. Ash admits that he would like to see it as well and decides to bring it back. Ash contacts Prof. Oak and decides to send over Unfezant. Oak replies that Charizard has just arrived from Charicific Valley and is certain that Staraptor and Swellow would be glad have another flying-type Pokémon like Unfezant. Ash comes outside to call out Charizard. Upon release, Charizard lets out a powerful roar, exciting Cilan, Iris and N. Charizard gives Ash its usual greeting of a Flamethrower to the face. N already senses that Charizard has a deep history with Ash, proving how great friends they both are.
Ash and Iris bring out all their Pokémon to meet Charizard. However, Charizard has his eyes on Dragonite, as they both have just developed a rivalry. Cilan and N see that the two are drawn to each other. Ash decides that he and Iris should battle so they can test their strength. Iris accepts and both take positions. Dragonite starts with Flamethrower, but is countered by the same move from Charizard. Charizard and Dragonite then fly up. Dragonite uses Thunder Punch, but misses Charizard, who counters with Wing Attack. Charizard then uses Slash while Dragonite uses Dragon Rush. The two moves collide, and Iris boasts that her Dragonite is strong. However, Charizard emerges without so much as a scratch from the attack. It then flies up and hits Dragonite with Dragon Tail. Both descend to the ground, and N calls off the battle, seeing that both sides are very powerful. Charizard and Dragonite agree, fascinating Cilan as they have made new friendships.
Iris wonders why didn't Dragon Rush didn't work on Charizard, claiming it to be a Dragon-type Pokémon. Ash, Cilan, Pikachu, Charizard and Dragonite are surprised, and so Ash explains that Charizard is actually a Fire/Flying-type. Iris still insists that Charizard must be a Dragon-type since it used Dragon Tail and even looks very much like a dragon Pokémon. When Ash uses his Pokedex to confirm his earlier explanation, Iris becomes shocked and a little embarrassed because she had hoped to catch and raise a Charizard, making Axew laugh at her. Ash asks Charizard if it wants to come with him for this journey. The others want this as well, as does Charizard, who accepts the offer.
- All the characters and backgrounds in the flashbacks are reanimated to fit the art style of the BW series. These scenes were also re-dubbed by the current TPCi cast instead of recycling the 4Kids voices.
- Instead of Rachael Lillis returning, Michele Knotz, who voiced Misty in Mastermind of Mirage Pokémon, voices her in the flashbacks of this episode.
- Although Team Rocket appears in a flashback, they are barely visible as in the scene they appear that they are being burned by Charmander's Flamethrower, leaving only their weak silhouette visible.
- According to Sarah Natochenny, this is her first time voicing Ash in the Original Series through flashbacks.
- This marks the first time Misty and Tracey appear in the BW saga.
- Who's that Pokémon?: Charmander.
- Though Liza did not have a speaking role, Lisa Ortiz provided the voice of the Kanto Fair Host.
- When Charmeleon finally evolves into Charizard it was different in both scenes where Charizard in this episode at the flashback it was seen to be roaring but in the original episode, Charizard is seen in a close-up while unleashing its Flamethrower after evolving.
- Unfezant is the 1st Unova Pokémon ever to have been send to Professor Oak's lab.
- With Charizard reunited with Ash, it means that its days in the Charicific Valley are over.
- When Ash and Koga's battle is shown, Charmander defeats Golbat with Flamethrower, when in the original episode, it wins with Fire Spin.
- When Ash tells Charizard that the others are waiting for him, his sleeve is mistakenly colored blue instead of white.
- When Charmeleon evolves into a Charizard after Aerodactyl taunts him, he was seen roaring angrily to evolve. But in the original episode, Charmeleon is seen stomping its feet several times while angrily roaring in order to evolve into a Charizard after Aerodactyl taunts it.
- When Ash gains the Volcano Badge after his Charizard defeats Blaine's Magmar, he was seen excitedly obtaining the badge. But in the original episode, the Volcano Badge that Ash obtained was given to him by Blaine after his Magmar was defeated by his Charizard.
- When Ash gains the Rising Badge, it's the same scene as when he gained the Volcano Badge.
- When he gains the Knowledge Symbol after Charizard defeats Noland's Articuno, Ash's blue sleeveless hoodie vest becomes indigo.
- When Professor Oak introduces Squirtle, Charmander, and Bulbasaur, he calls Bulbasaur a Grass-type. This is incorrect as Bulbasaur is also part Poison-type.