Here is the scene where Alva puts the Soul Heart on the machinery, which makes the flying fortress move goes in Team Robot In Pokemon Movie: Volcanion and the Mechanical Marvel.
(Now we hear Kimia's communicator rings and answers it)
Kimia: What is it, Flamel?
Flamel: Princess, I have something to report. A previously unseen design diagram by Nikola was found in Raleigh's room.
Kimia: Design diagram?
(The airship lands)
Alva: Nikola design the number of gadgets for defending the kingdom. The strongest of them being the wall that presently surrounds it.
Flamel: Part of the wall that defends the Azoth Kingdom can separate and turn into a floating fortress. It was design as a protections in times of an emergency, however an uprising broke out over just who would claim that power.
Alva: To stop the fighting, Nikola sealed the fortress so that it wasn't be able to move. Sealed in the darkness of history along with Magearna.
Meowth: Sealed it? What do you mean sealed?
Alva: 500 years ago, Magearna was not simply the Princess' playmate, it had another roll, to defend the princess as well as defending the Kingdom. How is it done? Using this. (He place the Soul-Heart on the mechanism and begins to activate) It's power has been sealed off. But by using Neo-Arcane science, it will finally be awakened!
(The Soul-Heart glows as the mechanical begins to activate and the walls turn into a flying fortress, we see the people of the Azoth Kingdom looks up seeing the flying fortress, then the heroes look seeing the event)
Emerl: Look.
Donkey Kong: What is that?
Ash Ketchum: Is that?
Clemont: It's Nikola's floating fortress!
Kimia: And to move the tower, they required the Soul-Heart!
Muscle Man: Oh, no, bro!
Rigby: This is bad.
SpongeBob Squarepants: Very bad.
Tai Kamiya: Everyone, come here and gathered around.
(Everyone gathered to the DigiDestined leaders and they tell them about their battle plans)
Davis Motomiya: Listen, we have a plan. We need to get on the Flying Fortress, once we enter to the lair, then we Rescue Tino, Jeri and the Soul Heart.
Max Taylor: Right.
Takuya Kanbara: Good, any questions?
Krader: (Raise his hands up) How are we going to take down Alva?
Takato Matsuki: That's a good question, Krader. Okay, just let me think for a minute. Alva painfully forces all the Pokémon to mega evolve one by one.
Flurr: We know.
Louie: How are we going to take him and the villains down?
Philmac: Yeah?
Takato Matsuki: Of course! That's it!
Eddy: What?
Takato Matsuki: So the Flying Fortress is way too high, and the Soul Heart, Tino and Jeri are Captured, so we might able get there and break a hole and go in there.
Zoe Drake Okay, but how are we going to do that?
Takato Matsuki: Simple, we might use the Mixels to max. Then head inside and stop Alva and his Gang, then we destroy his staff he's holding and BOOM! The Mega Evolution Pokemon Army are free from being controlled by him, and the villains will be so powerless!
Kazu Shioda: That's perfect!
Emerl: His staff was controlling his army. If we destroyed it, then he's finished.
(Inside the flying fortress the villains sees the heroes in the screen)
Major Nixel: What, I thought the Mixels are crushed for good!
Etemon: The pesky DigiDestined are alive?!
Myotismon: What?!
Zach Varmitech: The Wild Rats are alive?!
Miss Power: Wordgirl is still alive?
Natalia: (Shocked)
Dr. Drakken: Kim Possible is alive!
Spectre: So as those types and the old lady!
Ursula (Dinosaur King): Do I hear someone called me an old lady?!
Shego: Someone has to kill them again!
Alva: Still here, Princess? I see. (He activates the machine) Very well, after 500 years, I know what my fortress' first prey shall be. The Princess.
(Meowth was shocked and sees James and Jessie on the aircraft)
Meowth: Poor, Jess! Poor James!
(The soul-heart and the mechanism glows purple and the weapon appears. Then Ash and the heroes bring out their Pokemon Team, As Pikachu hops on Talonflame)
Ash Ketchum: You can do it, Pikachu!
Sora Takenouchi: Biyomon, go!
Biyomon: Okay!
(Biyomon digivolve to Birdramon, as the heroes get on her)
Tai Kamiya: Our turn!
(The heroes flies off to the flying fortress)
Ash Ketchum: Let's get going!
All Heroes: Right!
(Now we go back to the lair is where Alva chuckles evilly and closes his fist activating the weapon)
Alva: Now fire!
(Suddenly the screen begins to glitch)
Prince Hans: What?
Mr. Ross: What's wrong with it?
Alva: I said fire!
(The screen continues to glitch and the weapon couldn't fire)
Donita Donata: (In Fate 1's Voice) What's the matter with this weapon?
Paisley Paver: (In Fate 2's Voice) That Weapon won't fire!
Mr. Ross: Go and stop the heroes, from entering the lair. We'll take care of the Soul-Heart.
Chuck the Evil Sandwich-Making Guy: Okay.
Bowser Jr.: Let's move out gang!
(Meowth looks at the Soul-Heart)
Meowth: It's suffering! Magearna's suffering!
(As the Soul Heart began to turn black and turn to normal again and again, then flashback appears with fire)
Nikola: This power was purposely created to make all the people of the kingdom happy. But all they did was incite war and hatred, our citizens are wounded. (As Magearna try to talk to him, But he can't do it) Magearna. I'm afraid I have no choice but to hide you away, so the people aren't able to find you. I did my best, I'm sorry.
(Flashback ends as the Soul-Heart keeping turn black over and over as the screen glitches)
Meowth: Magearna's still in there! It said it doesn't wanna do this! It's suffering!
(As Alva looks at the Soul-Heart)
Alva: Magearna, so a piece of your heart is still remaining.