New episode title(s) has/have been added to the database. Title: サトシとバタフリー！また会う日まで！！/Satoshi to Butterfree! Mata au hi made!!. Please comment below! Thanks, your friendly PM.Net AnimeBot

A Caterpie is left behind at Migration Island. If it hasn't evolved into a Butterfree by the time the next rabble arrives, it's going to be all alone. Satoshi puts his heart and soul into helping it... and it eventually becomes time for an emotional farewell.

Summary:
Satoshi and friends have come to Migration Island, just in time to witness a rabble of the 'Cocoon Pokémon' Transel evolve into the 'Butterfly Pokémon' Butterfree. This island is known as a 'port of call' that migratory Pokémon like Swanna always stop by on their way. While Satoshi and friends are moved by this sight, a 'Worm Pokémon' Caterpie appears before them, having missed out on its rabble's evolution.

Satoshi, who remembers when he traveled with his own Caterpie way back, offers to help it evolve. Together with his friends, he immediately starts putting it through heavy training, but Caterpie's preference for sleeping makes for a rather cringeworthy moment. Further problems arise when they happen to enter the 'Hibernator Pokémon' Ringuma's territory...! The tiny Caterpie ends up confronting the gigantic Ringuma, however! What will happen next!?

Voice Cast:
Rica Matsumoto: Satoshi
Ikue Ohtani: Pikachu
Mamoru Miyano: Dent
Aoi Yuki: Iris
Minami Tsuda: Kibago
Megumi Hayashibara: Musashi
Shinichiro Miki: Kojiro
Inuko Inuyama: Nyarth
Rikako Aikawa: Butterfree
Kiyotaka Furushima: Koromori
Chika Fujimura: Joy
Masayuki Kato: Parker
Unsho Ishizuka: Narration

I have seriously mixed feeling about this episode. On one hand it brings back memories and nostalgic feelings. On the other hand it makes Ash do the same thing he has already done in the past, just in a smaller timeframe. Getting friends with a Caterpie (this time without catching it), training it up to Butterfree, then leaving it. Where there would be a great opportunity to reunite, or at least say hello to Satoshi's first ever caught Pokemon, there is just a brief flashback of it and the episode focuses on a completely different Caterpie. One which sleeps through most of the episode anyway.

If it wasn't for the lack of old Butterfree, this would actually be an excellent episode. Even Rocket Gang just played their role as a catalyst here without taking up too much time.

There were some interesting moments and PokéLogic though. A worm and a rat make a totally angry and pissed-off bear run away. Denies any real-world logic.
Once again the same situation: A random wild Ursaring appears in front of Satoshi, who has one hell of a Charizard up his balls and Iris, who has a Dragonite - the highest evolution of the only Dragon-type Pokemon from 1st generation. Instead of just battling the Ursaring like Pokemon trainers, they just run away in panic. Denies any Pokemon game logic.

My rating:
Could be a chance to see Satoshi's first caught Pokemon, but it is only a reminder of past events with a shadow of nostalgia. Despite that, it is quite a good episode.
I give it 8