Thomas and Twilight Sparkle meet Aquaman

Thomas and Twilight Sparkle meet Aquaman is an upcoming Thomas & Friends/MLP:FIM/DC crossover to be made by Hiatt Grey.

Plot
In 1985, Maine lighthouse keeper Thomas Curry rescues Atlanna, the queen of the underwater nation of Atlantis, during a storm. They eventually fall in love and have a son named Arthur, who is born with the power to communicate with marine lifeforms. Atlanna abandons her family and returns to Atlantis, entrusting her advisor, Nuidis Vulko, with the mission of training Arthur. Under Vulko's guidance, Arthur becomes a skilled warrior but rejects Atlantis upon learning that Atlanna was executed for having a half-breed son.

Thirty-three years later, Arthur confronts a team of pirates attempting to hijack a Russian Akula-class submarine. Their leader, Jesse Kane, dies during the confrontation while his son, David, vows revenge. Meanwhile, Orm, King of Atlantis and Arthur's half-brother, attempts to convince King Nereus of Xebel to help him unite Atlantis and attack the surface world for harming the oceans. Nereus points out that if Orm succeeds in uniting all four kingdoms, he will receive the title of Ocean Master, commander of the most powerful force on the planet. Their meeting is interrupted when another Russian Akula submarine attacks the meeting place, apparently in retaliation for the previous submarine's destruction. Orm succeeds in destroying it, and the attack convinces Nereus to join forces with Orm to defend the oceans. He swears allegiance to Orm's cause, but his daughter Mera, who has been betrothed to Orm, refuses to aid them and journeys to the surface to ask Arthur for help, earning his trust by saving Thomas from a tsunami sent by Orm. Arthur reluctantly accompanies Mera to a rendezvous with Vulko, who urges Arthur to find the Trident of Atlan, a magic artifact that once belonged to Atlantis' first ruler, in order to reclaim his rightful place as king. They are ambushed by Orm's men, and Mera and Vulko escape unseen, while Arthur is captured.

Arthur is chained and presented before Orm, who blames Arthur and the surface for Atlanna's death. He offers Arthur an opportunity to leave forever, but Arthur instead challenges him to a duel in a ring of underwater lava. Orm gains the upper hand and nearly kills Arthur before Mera rescues him. Together, Arthur and Mera journey to the Sahara desert, where the trident was forged, and they unlock a holographic message that leads them to Sicily, Italy, where they retrieve the trident's coordinates. Meanwhile, Orm meets David, revealing that the submarine that had attacked them previously was in fact the same one David hijacked and that Orm had hired him to hijack the Russian nuclear submarine so that he could stage a false flag attack from the surface, making it seem like Orm's cause for war is justified and causing King Nereus to side with him. Orm provides David with a prototype Atlantean battle suit to kill Arthur, imprisons Vulko after revealing knowledge of his betrayal, and coerces the Atlantean Kingdom of the Fishermen to pledge their allegiance to him and his campaign against the surface.

After modifying Orm's technology, a fully armored David rechristens himself as Black Manta and ambushes Arthur and Mera in Sicily, grievously injuring Arthur before being thrown off a cliff to his apparent death. Mera nurses Arthur's wounds as they journey to the trident's whereabouts and encourages him to embrace his destiny as a king. Arriving at their destination, Arthur and Mera encounter the Trench, amphibious monsters, but manage to fend them off and reach a wormhole that transports them to an uncharted sea located at the center of the Earth. There, they are unexpectedly reunited with Atlanna, who was sacrificed to the Trench for her crimes but managed to escape and reach the uncharted sea, where she has been stranded ever since.

Arthur faces Karathen, a mythical leviathan and keeper of the trident, and voices his determination to protect both Atlantis and the surface, proving his worth and reclaiming the trident, which grants him control over the seven seas. Orm and his allies lead an army against the crustacean forces of the Kingdom of the Brine with the intent of completing Orm's surface battle preparations. As Orm declares himself Ocean Master, Arthur and Mera, with the assistance of Karathen and the Trench, intervene and lead an army of marine creatures in a battle against him. Orm's followers renounce their obedience to him and embrace Arthur as the true king upon learning he wields the trident. Arthur defeats Orm in combat but chooses to spare his life, and Orm accepts his fate after discovering Arthur has found and rescued Atlanna. Atlanna returns to the surface to reunite with Thomas while Arthur ascends to the throne with Mera by his side.

In a mid-credits scene, David is rescued by Dr. Stephen Shin, a scientist and conspiracy theorist obsessed with the Atlanteans, and agrees to lead Shin there in exchange for his help in his revenge on Arthur.

Trivia

 * Princess Celestia, Princess Luna, Barret Barricade, Princess Sharon, Knockout, Puffer, Dolphy, Rachel, Mighty Joe, Daylight, Jenny, Pete, Kevin, Morley, Blitzer, Dile, July, BZ-7 (Buzz), R5-K5 (Kratt), Blythe Baxter, Zoe Trent, Pepper Clark, Penny Ling, Vinnie Terrio, Sunil Nevla, Minka Mark, Russell Ferguson, Gail Trent, Mitzi, Buttercream Sunday, Sugar Sprinkles, Olive Shellstein, Captain Cuddles, Nutmeg Dash, Youngmee Song, Sue Patterson, Jasper Jones, Tempest Shadow, Grubber, Songbird Serenade, Capper, Captain Celaeno, Princess Skystar, Queen Novo, Belle, Flynn, Butch, Rocky, Captain, Harold the Helicopter, Whiff, Scruff, The Steam and Pony Rebel Alliance "B", Team Griffin/Eeveelution, The Griffin Family, Glenn Quagmire, Cleveland Brown, Joe Swanson, the Young Six (Silverstream, Smolder, Ocellus, Sandbar, Gallus, and Yona), Terramar, Chinta, Rikki Tikki Tavi, Sapphire, Team Nelvana, Mitzi, No Feet, Tutu, Todd, Maurecia, Myron, Dana, Doug Funnie, Skeeter Valentine, Roger Smith, Bender Bending Rodríguez, Minerva Mink, Master Shake, Meatwad, Frylock, Pazu, Sheeta, The Crystal Prep Girls, Panty, Stocking, Ami Onuki, Yumi Yoshimura, Wubbzy, Widget, Walden, Daizy, Gordon Quid, Waffle, Mr. Blik, Kim Possible, Rocko, Heffer, Filburt Turtle, Ren and Stimpy, the Digimon Tamers and the Digimon (Takato Matsuki, Rika Nonaka, Henry Wong, Guilmon, Terriermon, and Renamon), Calumon, Impmon, Mikey Simon, Gonard, Guano, Lily, Mitskui, Ozu, Yes Man, the D-Team and their dinosaurs (Max Taylor, Chomp, Rex Owen, Ace, Zoe Drake and Paris), One, Two, Three, Four, Five, Six, Seven, Natsu Dragneel, Lucy Heartfilia, Gray Fullbuster, Erza Scarlet, Wendy Marvell, Happy, Carla, Bob the Builder, Scoop, Muck, Dizzy, Roley, Lofty, Wendy, Pilchard, Bird, Travis, Spud the Scarecrow, SpongeBob SquarePants, Blackie the Lamb, Patrick Star, Squidward Tentacles, Sandy Cheeks, Mr. Krabs, Trixie Tang, Jenny Wakeman, Dudley Puppy, Kitty Katswell, the Powerpuff Girls (Blossom, Bubbles, and Buttercup), Lazlo, Raj, Clam, Mordecai, Rigby, Benson, Skips, Pops, Muscle Man, Hi Five Ghost, Margaret, Eileen, Gwen, Trent, Owen, Izzy, Lindsay, Tyler, Beth, Duncan, Courtney, Leshawna, Harold, DJ, Geoff, Bridgette, Noah, Katie, Sadie, Cody, Sierra, Zoey, Mike, Cameron, Sam (Total Drama), Dakota, B, Jo, Brick, Anne Maria, Staci, Princess Anna, Vanellope von Schweetz, Judy Hopps, Nick Wilde, the Puzzle Place gang (Julie Woo, Kiki Flores, Ben Olafson, Leon MacNeal, Skye Nakaiye, and Jody Silver), Duck, Donald and Douglas, Oliver (Thomas & Friends), Toad, Stepney, Duke (Thomas & Friends), Smudger, Mighty Mac, Fearless Freddie, Daisy, Jack, Alfie, Spencer, Arthur, Murdoch, BoCo, Derek, Molly, Hector, Hank, Flora, Princess Ember, Gabby, Minuette, Lemon Hearts, Twinkleshine, Barrington, Northumberland, Pugwash, Rebecca, Constance, Ariel, Prince Eric, Melody, Flounder, Sebastian, and Ariel's Sisters (Attina, Alana, Adella, Aquata, Arista, and Andrina) guest star in this film.
 * This film marks it's first appearance of Dile.
 * The Powerpuff Girls Movie and Aquaman were both released by Warner Bros. Entertainment.