If you're wondering what Duel of the Fates is, or what Colin Trevorrow has to do with Star Wars Episode IX, you should probably go check out our brief backstory article first. Duel of Fates is the Episode IX that Trevorrow was supposed to write and direct before he parted ways with Lucasfilm over creative differences. He was on the project for just over 2 years, and apparently had fleshed out a nearly complete story in that time.
The leaked concept art and plot points were confirmed - at least in part - by Trevorrow himself. He verified the script title, a couple plot points and several pieces of concept art. More importantly, he didn't deny any specific element of the leaks, except that he wasn't going to kill off R2-D2.
John and Eric recorded a special podcast episode to go over these images in more detail, if you want to listen along. [*** Warning: Contains spoilers for The Rise of Skywalker ***]
The film opens with Rey on the bridge of a Star Destroyer, surrounded by dead stormtroopers. She is wielding a double-bladed blue saber that appears to be something of an amalgamation of her staff and Luke's lightsaber. This scene presumably takes place in the Kuat Drive Yards, where the Resistance is purportedly attempting to cripple the First Order's main source of starships and vehicles.
On Coruscant, we see a massive First Order Capital ship looming over the planet. Their occupation of the Core world and former capital of the galaxy is apparent.
In the next scene, we see a resistance traitor named Bisc Kova about to be publicly executed by way of a laser guillotine. Although it's not specifically mentioned in the script leaks, the character standing next to him appears to be Captain Phasma (note the helmet damage).
On the planet of Koralev, Rey hones her skills under the tutelage of Luke (or perhaps, force ghost Luke). She appears to be wielding a yellow, single-bladed saber in this piece. Geek side note: While it could be mere coincidence, Sergei Pavlovich Korolev is the founder of the Soviet space program.
On the planet Remnicore, Kylo finds Tor Vallum, an ancient dark side being that is hundreds of years old. He tells Kylo that he must let go of his past and embrace the dark side to advance his power. He tells Kylo about Mortis and teaches him how to drain the life force from another living being.
Back on Coruscant, Finn, Rose, C3PO and R2-D2 make their way through the "underground." They are attempting to get to the Jedi Temple so they can send a transmission from Leia across the Galaxy - a call to arms for those that support the Resistance and oppose the First Order. Along the way, they see how terrible life has become for the people of Coruscant and it strikes a nerve.
During his training with Vallum, Kylo comes across a convergence in the force - a cave similar to what Luke and Rey went through. He confronts Darth Vader inside, but loses the confrontation. Consumed by his anger and frustration, he kills Tor Vallum using the life draining ability he taught him. His commitment to the dark side is complete and he leaves Remnicore to seek out Mortis.
Elsewhere in the galaxy, Rey, Poe, Chewbacca, and BB-8 head to the Outer Rim planet of Bonadan seeking a seer that can guide Rey to her path. The script notes that Poe used to live here with his Grandfather.
On Coruscant, Finn and team finally arrive at the Jedi Temple. They send Leia's transmission across the galaxy. The message is received far and wide, but the First Order is able to cut it off before the transmission is complete. Did enough people hear the call? Will they come?
On Bonadan, the Knights of Ren find Rey and the others. The heroes take to the water in a Razor Sail as they attempt to escape. The chase sequence ends with Rey confronting the Knights and defeating all of them in melee combat.
Disturbed by the bleak conditions on Coruscant, Finn and Rose convince the people of the underground to stage a revolt against the First Order occupation. They apparently manage to convince a contingent of stormtroopers to turn against their former masters, as well.
The new Coruscant rebellion modifies stolen First Order and Imperial era weapons of war, in preparation for an impending battle with the First Order's occupying forces.
Presumably, based on information from the seer, Rey eventually makes her way to Mortis. She must confront a massive beast outside the forest of Mortis. While they have not run into each other yet, Kylo is also here.
The battle of Coruscant begins. Clearly, the rebellion has the high ground. You can see the now-turned stormtroopers on the right side of the scene, with their helmets removed. Above the planet, another battle is raging - people have answered the call to arms and come to help the Resistance.
It's not entirely clear if this is a victory scene or a rallying cry during the battle. But in any case, the Rebel force led by Finn and Rose defeat the First Order forces on Coruscant.
Rey and Kylo meet on Mortis. They are evenly matched. It is revealed in their dialog that Kylo killed Rey's parents upon orders from Snoke. Her last name is also revealed in this scene: Solana. Kylo retreats from the stalemate and enters the nearby temple, where he believes he will find the power he seeks.
R2-D2 is badly damaged during the battle of Coruscant. He appears completely lifeless as C3PO mourns over his darkened shell. Reminiscent of the Empire Strikes Back, Chewbacca will strap R2-D2 to his back and haul him back for repairs. This is why Trevorrow said he didn't kill R2-D2 - he is repaired by the end of the film.