S1EP02 Tidal Currents

Tidal Currents is the second Episode of the first season, and revolves around teamwork, and a bunch of water-pokemon Ashley and her Piplup (Splash) Encounter. WARNING: May contain spoilers or Plot endings

Plot Description
The episode begins with Ashley and her Piplup heading off towards Orebeurgh City for their first Gym battle in the sinnoh region. But as they walk, they come across a lake filled with Marshstamp, Mudkip, Squirtle and Wartortle. Though the lake is very pretty itself, it's not so pretty when you know what's really up.

It seems that the Wartortle are trying to push the Mudkip and Marshstamp out of their lake, because they believe that this lake was only suited for the Squirtles, themselves, and any Blastoise. The Marshstamp and Mudkip try to fight back, but one of the older Marshstamp's evolves into a Swampert, and begins to cause havoc and chaos among all the Water Pokemon in the lake.

Though normally Marshstamp don't evolve unless they're with a trainer, the newly evolved Swampert starts ordering around the Wartortle, until they get sick of it, and attack the swampert anyways. After a long battle between the water-types, Ashley's Piplup seems eager and willing to get involved, to stop the chaos. Once Ashley freely lets Piplup go to stop the havoc, the water-pokemon look at Piplup with worry and disgust from the wartortles. They begin using their water gun against Piplup, but Piplup learns Bubble, and manages to fight back against the angered Pokemon. And at the end of the episode, the Swampert has an agreement with one of the older Wartortles, that there will be no more fighting. A smaller Squirtle decides to come along with Ashley after seeing what her Piplup can do, and she gladly accepts, the Squirtle letting her catch it.

Details
Ashley's Squirtle was an accident to recieve, because she had just been expecting to help out and then be done with the lake full of water-pokemon. She really hadn't meant to attract any Pokemon to her, especially not a Squirtle as small as the one she had recieved was.

Splash (Ashley's Piplup) later forgets Bubble to be replaced with other moves, meaning Splash only new Bubble for a few episodes before forgetting how to use it entirely, moving onto more powerful moves (Such as Hydro Pump and Rock Smash).

Ashley's Squirtle never evolved into a Wartotle naturally, only when it accidentally found a water stone did It evolve. It is unknown if the water stone Squirtle found was actually the cause of evolution, or it was just ready to evolve at that specific time.