XY118/Plot

The episode begins with Olympia speaking with Diantha at the Anistar Gym about her vision of the future crisis of Kalos. When Diantha asked about "Those deep green eyes", Olympia showed her an image of, which made Diantha impressed by recognizing it.

Then is shown a scene with and his  stretching and racing each other, with Ash believing he could master the Ash-Greninja form if he "becomes" Greninja. They stay at the same speed until Greninja starts jumping from branch to branch, with Ash mimicking Greninja, but he fell from a branch and Greninja helped him to stand up. , and  are waiting Ash and Greninja on a glade, with Bonnie worried about Greninja's and Ash's delay, with Clemont finding the idea of "become a Pokémon" an absurd and Serena wanting Ash to not overdo with that idea. Greninja reached to the group first and Ash, very tired, reached last.

Then, Diantha reached the glade in a helicopter, jumping from it. Squishy was hiding in the bag. Ash asked Diantha why she was there, and she's says that she is there to find them and she says that she listened to Olympia's prophecy. is nearby, observing them. Diantha speaks about the Kalos Crisis and she shows an image of an island attacked by Team Flare's weapon. She mentions that's this its not the only place in Kalos with that state. She says that the danger mentioned on the prophecy refers to when Zygarde begins to act. She shows an image of Zygarde to the group and starts to explain its role. Team Rocket recognizes Zygarde as the Pokémon that Team Flare kidnapped.

Clemont remembers the prophecy and how Olympia says that they are involved somehow in the crisis. Diantha asks if something changed around them, and Bonnie comments about Ash's Greninja being amazing, and they explained her the phenomenon. Clemont remembered what Olympia said about them when Greninja was a. Diantha asks Ash to show Greninja to her in a battle against her. Team Rocket start planning to steal Diantha's when it Mega Evolves. Diantha's notes the Battle Pulse Meter and asks about it, so Clemont explains how it works.

The battle starts, with Greninja trying to hit a few hits, with Gardevoir quickly dodging them. Diantha comments that Ash's Greninja is well created, but doesn't feel any difference on the others. So, she started to attack with a and Ash tells Greninja to use  to dodge the attack. Diantha responds by having Gardevoir to use a Shadow Ball sequence to destroy the clones. Ash says to Greninja to use a sequence in return, bu was dodged by Gardevoir. Gardevoir uses, which was dodged by Greninja, but it was hit by the shock wave.

Ash helps Greninja to stand up stating he has an idea on how to get close to Gardevoir. He tells Greninja to use Water Shuriken, which is dodged and creates a vapor cloud. This distracts Gardevoir and obscures its vision, allowing Greninja to finally land a hit with. Greninja transforms into its Ash-Greninja form. Diantha and Team Rocket are all surprised at seeing this unknown form. Ash tells Greninja to use Cut, which is blocked by Gardevoir's Shadow Ball but still manages to deal damage. Diantha tells Gardevoir to use Shadow Ball, which is blocked by Greninja's Water Shuriken. Then Greninja goes towards Gardevoir using Cut, which is almost dodged, but Gardevoir takes another hit. Ash tells Greninja to use on Gardevoir, and with the pressure against Gardevoir piling on Diantha decides to Mega Evolve it and the attack is blocked.

Ash, feeling that the battle is really starting now, has Greninja use Water Shuriken, with Ash and Greninja moving in perfect sync while the attack is executed. The attack is blocked by Gardevoir's Shadow Ball, so Greninja uses Aerial Ace, which is blocked by. Greninja uses Double Team and later Cut. Gardevoir tries Reflect again, but the protection was destroyed by Greninja's attacks. The water veil around Greninja lifts and creates a giant Water Shuriken on Greninja's back. It uses its new Water Shuriken to attack Gardevoir who fires a Shadow Ball to block Greninja's attack, but this fails and Gardevoir is sent flying. As his opponent lies stunned, Ash is ready to defeat Gardevoir and tells Greninja to use Cut. However before Greninja can begin, the energy between them becomes too much and both Ash and Greninja faint. While Diantha is going to check if Ash is okay, Gardevoir is captured by Team Rocket, but Gardevoir is easily able to escape from Team Rocket's "Unbreakable Mega Ring" and uses Shadow Ball to blast them off. Ash and Greninja recover, and Diantha says goodbye to the group and t suggests that they keep researching Ash and Greninja's power, for Kalos', Ash's and his group's sake.

It's shown a quick scene of Lysandre saying that it is time to go to the final stage and Ash promised to Greninja that they will become stronger and master their power as they prepare to leave.