This is how Opening: King Solar Flare gets help and the Knights win the battle goes in My Little Pony Transformers: The Last Knight.
[We see a battle going on between Demon Changelings, teamed up with Minotaurs, against the Equinelantians]
[We see some Equinelantians firing off catapults at the enemy]
[We then see King Solar Flare and his men watching the battle]
Discord: We won't be able to win this one.
King Solar Flare: Starswirl will come, Discord. We must have faith.
Young King Sombra: I agree.
[We see Starswirl running through the forest]
[He stops for a moment to drink his water]
[Cut back to the battle]
[We then see another wave of Minotaurs joining the battle]
Discord: Another wave.
King Solar Flare: We must keep our faith strong.
Young Queen Chrysalis: I would lay down my life for you, your highness. But this is suicide.
King Solar Flare: We must buy Starswirl time. He has never let us down before.
[Together, they all charge at the enemy]
[Back with Starswirl, he is seen running up to a well hidden spaceship]
Lord Macintosh: (narrating) Magic is real. It arrived long ago on a crashed alien spaceship.
[He runs into it]
Starswirl the Bearded: Hello?! It's me! The wizard! Master of Time!
[Back at the battle, things are not looking great]
Discord: We must retreat. We will at least live to fight another day.
King Solar Flare: [drives a spear into the ground] No sacrifice. No victory. We will wait for Starswirl.
[Back at the ship, a robotic hand slams Starswirl into a wall]
Stormreign: I told you never to come back!
Starswirl the Bearded: I told no one of your existence! I swear!
[Stormreign releases him]
Starswirl the Bearded: I know you told me to never come back, but we're in a desperate battle right now. My friends are down there and are counting on me to help them. I am what they say. I am a mere mage, not a wizard. But if I could make a change in the world for the better, I would give up everything, everything! I would give up want, money. I know your world was destroyed. I'm sorry. But if you don't help us, good men will die. Women and children too. Please don't let my world be destroyed.
Stormreign: Guardian Knights, transform.
[He hands Starswirl the staff in his hands]
Stormreign: Dragon is yours to command.
Starswirl the Bearded: Yes. That just might be the thing we need.
Stormreign: Protect this staff. One day, a great evil will come for it.
[Dragonstorm flies alongside Starswirl who raises the staff in victory]
Starswirl the Bearded: OH YES!!!
[Dragonstorm flies to the battle. Back at the battle, King Solar Flare sees the talisman on his armor glowing and draws his spear, Grundir]
King Solar Flare: CHARGE!!!
[His forces charge at the enemy as Dragonstorm attacks the Demon Changelings]
Lord Macintosh: (narrating) The Transformers have been here for a long time. Since the Dark Ages.
[1600 YEARS LATER appears on the screen as we see Optimus and Twilight floating through space, motionless]
Optimus Prime: (disjointed) I am Optimus Prime. And I send this message to my Creators. Leave Planet Equestria alone. Because me and Twilight are coming for you...
[MY LITTLE PONY TRANSFORMERS: THE LAST KNIGHT appears on the screen as we see a wide shot of Equestria]
Lord Macintosh: (narrating) These are troubled times. Optimus Prime left with Princess Twilight Sparkle to find his creators. Some say he will never return. While Megatron, leader of the Decepticons has been brought back to life, and Omegabot breaking into the former FPI building in Manehatten and stealing Starscream's head and Lockdown's body. And the Transformers are illegal on Equestria.
[We see an Autobot fight off two Decepticons]
Lord Macintosh: (narrating) The world has set up a new task force. The TRF, aka the "Transformers Reaction Force".
[We see a former Tartarus Wind member and his squad listening to a high ranking commander]
Lord Macintosh: (narrating) Except in Atlantis, which has become a safe haven for them.
[We see an Autobot playing volleyball with Roadbuster]
[We then see Topspin kicking a soccer ball]
Topspin: Yo! Come on! Let's go, it's beach time!
Mera: He's busy!
Topspin: He's always busy!
[We see Discord looking at a map and drinking a rootbeer float]
Discord: A rootbeer float needs ice cream! Ice cream! This is just root beer with whipped cream in it!
[We then cut to Cybertronians falling from the sky]
Lord Macintosh: (narrating) But they continue to fall from the sky. Too many to count. Yet, they always come back here. To Equestria. Why? I fear the answer is upon us.
[We cut to a NASA computer lab, with a nerd pony listening to some music, and likes it]
Nerd Pony: Yeah, this is good. Good choice.