A rumble of thunder is heard in the sky with the clouds forming together to form a storm as lighting shot down, striking onto melemele Island and the rest of the Alola Region as the adult finally snap out of their laziness and started to run including the pokemon as we see Arfoire which she is now fused with Necrozma as she cost chaos to everything around her.

She let out laughter as she cost chaos and destruction all around her while people ran away from her. A few people were taking to the pokemon Centre as Officer Jenny and Nure Joy got everyone inside and we see everyone inside the pokemon centre.

While the goddess were battling Arfoire outside, helping the people to evacuate, we cut to Y/n laying unconscious while having bandages wrapped around his waist as we see Ash and the Ultra guardian gathered around him, worrying about Y/n's life.

Kukui: Ash, everyone!

Then Kukui, Burnet, Lusamine, Wicke and Faba enter as they get close and see the unconscious and injured Y/n as Burnet cover her mouth in shock.

Burnet: (shocked) What happened!?

Ash: He got stabbed during his battle against Arfoire.

Mallow: Lucky he'll be alright.

Kiawe: Still Arfoire is powerful, especially with her fused with that Ultra beast.

Lusamine: This is not good. If they are extremely powerful together, then I don't know how we can win.

Wicke: There has to be a way! Maybe we can trap them into a Ultra world portal? Maybe that will work.

Lusamine: It's our only one shot. We must tell Neptune and the others about this as soon as we can.

Faba: Right.

Faba race outside while Ash turns to Y/n and places q hand on top of him as he, Pikachu and Poiploe were worried for him. Then Ash's Z crystal glow all of a sudden which he removed his hand but the Z Crystal's glow disappeared while everyone was surprised.

Lana: (surprised) Did you guys see that?

Sophocles: (surprised) Yeah! It glow bright but it disappeared when Ash move his hand away from Y/n.

Ash: Weird.

Then there was a knock at the window which they turn and open the window to see the four Ultra guardians Tapu Koko enters the room and places a hand on Y/n's head and nodes and then turns to Ash and tells him something which Ash and the others doesn't know what.

???: Tapu Koko wishes you to use the Z move to give Y/n power.

They turn to see Hala in the room with them as he explains Ash.

Hala: I believe Tapu Koko wishes you to use the Z move crystal to not only heal his wounds but also make him stronger to defeat this new threat.

Kiawe: (surprised) Seriously?! Is that even possible?!

Mallow: (surprised) Yeah how can it be possible?

Ash: Hold on, Neptune told me that he once fused the Share crystal which make him stronger while given him a new form.

Hala: It seems so. Although the Share crystal and Z crystal are two complete different items, but they do share the pure of energy. If that is the case, then it is possible to recover him while also making him stronger.

Gladion: Ash, we should do this together.

Ash: Right.

Once that Ash, Gladion, Kiawe and Lana place their hand on Y/n while everyone else grabs Lana, Kiawe, Gladion or Ash's shoulders so they can help. Soon the Z crystal glow and Y/n can feel its power as three Island guardians enter and they turn into  their shells and spin around Y/n as Ash the other focused as best they can.

Their Z crystal glow even more while Y/n can feel not only the power of the Z moves but also everyone on the island, Ash and the others as he sees glimpses of their memories, those they have been through and the journeys they have gone through especially Ash.

Soon his body started to glow red as everyone sees this and steps back as there was a massive red glow and then Y/n's eyes open, filled with determination within them.

(Meanwhile)

The goddess, Nebby and Lunala battle Arfoire as they launch every attack at her but yueir attacks didn't do nothing as she launches towards them and beats them up, tossing them aside as they crash heard onto the ground.

The goddess were laying on the floor badly hurt as Arfoire is over them as she smirked at them as she reach out her hand and charge up her final attack while the goddess, Nebby and Lunala look up to see this.

Arfoire: (smirk) This is where it ends here. Its unfortunate that I have to kill you all here on a peaceful world. I hope your vacation was nice until it last.

Purple Heart: You'll never win Arfoire! Even if you try your best, in the end you will be defeated.

Arfoire: (smirk) Is that so? Well it seems that's never gotten happen. As soon I'm done with you all, I'll kill your sisters and soon take over both worlds. It will be my empire. Now enough talk, time for you to di-

Immediately she was punched in the face and was sent flying away from Melemele island as Purple Heart and the others look up to see Red Heart but in a new and even more powerful form.

Purple Heart: (surprised) Y/n?! How?

White Heart: (shocked) How many forms will he have!

Orange Heart: (smile) Now that's one super cool form Y/n~!

Red Heart: Thanks. Now as for you Arfoire.

Arfoire fired her blast at Red Heart but he slaps it away with won swing whidh shocked her. Then he appear in front of her and then strike a punch at her in the face.

She was spinning upwards but he grabbed her foot and then he spins her around and then tosses her further away but Arfoire stop herself and charges up while Red Heart also charges up and then the two charge at each other and seconds later there was a huge blast and after that everyone can only see some glimpses of them as they quickly disappeared and reappear in different area as they strike blows at each other.

Arfoire swings her spear, trying to strike at him but he grab her spear and holds it while the two looked at each other as he immediately breaks it into two and then strikes a blow at her.

She was sent flying only for a Red Heart appear behind her and grab her at the back of the head. Then he tosses her upwards and then flies up and strikes a powerful blow at her.

Arfoire had enough and pushes Rdd Heart back and then open a Ultra wold portal behind her and tries to retreat but Red Heart calls out.

Red Heart: Not so fast!

He flies after her as they battle within the Ultra world portal as they strike blows at each other. Soon they editbout of the other side which is filled with crystal as they land hard onto the ground as Red Heart pushes Arfoire back and then strike some powerful punches at her.

Red Heart continues to strike blow after blow at her as he dodges her strikes and continues to strike blows at her. He then kick her back which she stumbled backwards as she forms a fist and glare at Y/n as she yell out in rage.

Arfoire: (angry) I will not be beaten by the likes of you!!!!

She then fired her massive blast at Red Heart which he catch it with both of his hands as he hold it long. His feet started to slip back a bit as he holds it even more and soon the goddess and the Ultra guardians came as Ash and Gladion rush over to Red Heart.

Ash: Y/n let's finish this together!

Gladion: We need to end this now!

Red Heart: Understood! Do I hurry!

Ash: (smirk) Alright then! Let's do this!

Both Gladion and Ash use their Z crystals as they do the same moves together and once they were done the massive energy goes towards Red Heart as he let's out a yell as he tosses the beam away and then put his hands at Arfoire and charge up a beam and then fired a massive blast at her.

She's shocked by how powerful this beam is and immediately she gets hit by it and was sent flying as she and Necrozma split apart and defeated.

Red Heart was breathing heavily as he and the rest see Arfoire and Necrozma is defeated. Soon Necrozma gets up and starts at Red Heart and the others and then flies off, opening another Ultra portal and leaving while Red Heart walks over to the still unconscious Arfoire and then turns to everyone and gives them a thumps up.

Everyone smiled in glad but suddenly the crystals around them start to disappear and soon after the whole world was changed to a peaceful world with plants and a large tree in front of Y/n.

Mallow: Guys look!

They look around and sees movement and soon they see Poiploes coming out which shocked everyone. Then an evolved Poiploe appeared in front of Red Heart as it and the others looked at them.

Rotom dex: (surprised) This is incredible! More Poiploe, misu take some pictures!

Green Heart: This must be Poiploes home then.

Black Heart: Seems like it.

The evolved Poiploe sees Ash's Poiploe and the two seem like they are talking. They all watch this happen and then Ash's Poiploe looks upset which Ash realised what is happening as the two look at each other as Ash smiled and tells him.

Ash: (smile) Don't worry. I understand you wanted to stay here Poiploe. No matter what, we're always friends.

Pikachu: Pikachu.

Ash's Poiploe started to cry and then hugs Ash. Red Heart sees this and it reminds him of Jiggles. Soon they leave this world and Ash's Poiploe as he draws a drawing, telling Ash he will meet him again which Ash nodes as they return back to their world.

(Later)

They return back and we see everyone gathered at the beaches of Melemele island as Burnet gets the portal open for Y/n and the goddess as Unzume is seen holding the unconscious Arfoire as Y/n and the goddess turn to the Ultra guardians.

Lusamine: (smile) We wish to thank you for everything you have done for us.

Neptune: (smile) It was nothing! It's good we have a crossover arc and fighting side by side.

Mallow: (smile) We gonna miss you all so much!

Lillie: (smile) Yeah, you all were amazing and fun.

Vert: (smile) It's our pleasure.

Noire: Well let's heaf back home.

And then the Goddess leave while Y/n walks up to Ash and Pikachu as he reach out his hand to Ash and tells him.

Y/n: (smile) Good luck on your journey Ash and Pikachu. Hope you two will be the greatest duo of all time.

Ash: (smile) Yeah we will.

He than takes Y/n's hand and the two shake on it as Y/n turns to the portal to leave but he stop and turn to Ash and tells him.

Y/n: (smile) Ash! I have faith that you will be the pokemon master!

Ash smiled back and noded as Y/n walks through the portal and then the portal closes as he and goddess all return home.

(Hyperdimension Dimension)

They return back and once they were back Histoire looks surprised as she flies over to them and asked.

Histoire: That was quick? I suspect it will take you days to find him.

Neptune: What do you mean?

Noire: We were in there for a week?

Histoire: To me you were in there for 3 minutes.

They were shocked by this amd confused as the portal behind them closes. They turn to where the portal was as the goddess leave to return back to their own nation while Y/n stay there for a bit as Neptune walked up to him and then ask him.

Neptune: You'll think he'll succeed his dream?

There was slince for a moment and then he smirked as he turn to Neptune and then tells her.

Y/n: (smirk) Sure he will. He'll be the best like no one ever was.

Neptune smiled and the two head back to Planeptune to play some videos and chill. We see Arfoire being taking to prison as she sat down on her prison bed while we cut back to Y/n at the balcony and watching the veiw. Disbite being back home, he can still feel the Z crystal engery within him and knows this was the gift of Ash and the others so he can get stronger and protect the people he care for. He then smiled to himself and enter back inside to rest as he wonder how Ash is doing at the other side.

(Alola world)

A year gone by as we see Ash and Pikachu return back to Alola just to visit his friends at Melemele island. He was making his way through the city when he stop and he and Pikachu noticed something as they look up.

???: Hey Ash!

Then Goh rushes over to Ash and gets beside him and then looks up and was amazed to see a statue of the goddess will Red Heart at the top as Goh ask Ash.

Goh: (surprised) Wow they look cool! Who are they?

Ash remember his time with them as he just smiled, turned to Goh and tells them.

Ash: (smile) Let's just say, they are friends from another world.

To be continued................................................