Full summary, thanks to redon from Arlong Park Forums.
Chapter 1,025: "Picture of Two Dragons" (双龍図).
In the cover, Usopp is telling his adventure story to members of a publishing team (2 shocked birds that are taking notes in a notebook and an octopus that is typing in a typewriter). Usopp is dressed as a pirate captain (he wears a hat like Roger's but with his own Jolly Roger) and on his head is a paper that the octopus has written where it reads "Big liar story".
Chapter starts with Luffy pushing Momonosuke to fly up to Onigashima. Momonosuke tries but he can't because he is still afraid of height. Shinobu and the Heart Pirates watch the scene in silence.
Cut to Onigashima's rooftop, just after the clash of Kaidou and Yamato “Raimei Hakke” that we saw at the end of the previous chapter. Kaidou bleeds from his forehead, Yamato's skin begins to crack until it shatter into pieces. Yamato used a technique called “Kagami Yama” (Mirror Mountain - 鏡山) a move that seems to cover his body with a glass-like shield so he receives no damage.
Before the shield is completely broken, Yamato jumps up and breaks free from the crystals. He then spins his kanabo in the air and hits Kaidou with a new attack called “Himorogiri” (Cutting Massive Ice - 氷諸斬り) stamping Kaidou's head in the ground.
However Kaidou gets up once again and attacks Yamato with his kanabo repeatedly.
Kaidou: "No matter how much you uses other names
or tries to become a samurai...
You can't deny the fact that you're the son of Kaidou.
You still have “Oni (鬼)” blood in your body!!"
Yamato: "It doesn't matter to me!!!"
Yamato manages to hit Kaidou in the face with his kanabo, but he keeps talking.
Kaidou: "You have always been alone, running and hiding in the castle."
Yamato replies, while we see a panel with kid Yamato reading Oden's diary secretly.
Yamato: "That's not true!!
I have a friend!!! "
As he says this, Yamato remembers Ace. Kaidou replies him.
Kaidou: "Yeah, but your friend is dead...
Along with those samurai and people who were nice to you!!"
We see a little flashback in which a Kaidou's subordinate who was kind with Yamato and gave him food secretly, was executed for it (on a wooden crosshead like the one Jack used to torture the Minks in Zou). Yamato saw it.
Kaidou hits Yamato on the head with his kanabo and Yamato falls to the ground. Kaidou hits Yamato repeatedly and violently while he is on the ground. Kaidou looks like a real ogre.
Kaidou: "You are a child of an “Oni (鬼)”!!
You must rule human by force, not getting along with them!!
It is your destiny, Yamato!!!"
Back to Luffy and Momonosuke, who finally manages to fly. However, Momonosuke flies with his eyes closed because he is still afraid of height. Momonosuke flies so fast that they reach Onigashima in seconds, while Shinobu looks at them from Wanokuni in silence and with a very serious face.
When Momonosuke flies over Onigashima's island, Luffy tells him that they should go to the roof of the dome. But Momonosuke flies with his eyes closed and ends up entering in the skull, inside the castle. In a very funny double page we see how Luffy (that is screaming) bursts into the “Live Floor” on the back of Momonosuke (who is still with his eyes closed) while we see the reactions of Queen, Sanji, Hyo, Kawamatsu, Izou, Marco, Zoro and King.
Momonosuke flies across the “Live Floor” while Luffy tells him that they have to go up. Momonosuke is a bit dizzy but manages to straighten out and climb. Both go through the 2nd floor of the castle, right in the place where Big Mom continues fighting against Kid and Law.
Kid: "What the hell!!?"
Big Mom: "Kaidou!!? What is going on!?"
Momonosuke continues his uncontrolled flight while all who see him are shocked. Luffy tries to help Momonosuke, but some of the debris got into Momonosuke's eyes and he just keeps crashing all over the castle.
Back to Onigashima's rooftop. Yamato turned back into his human form and prepares to attack again his father. We see in the distance behind Yamato that Momonosuke has managed to cross the castle and reach the rooftop (Luffy continues screaming). Kaidou has noticed it and looks them surprised. Luffy sees Kaidou and tells Momonosuke to go after him. Momonosuke does it, this time with his eyes wide open.
Yamato and Luffy attack Kaidou without either of them being aware of the other's presence.
In an impressive double page, Luffy and Yamato hit Kaidou at the same time in his face, their attacks create black lightning bolts. After the attacks, Yamato notices the arrival of Luffy, something that makes him very happy.
Luffy: “Yama-o!! You helped stop Kaidou? Thanks!!”
But there is no time for reunions. In a new double page, Kaidou transforms into a dragon and confronts Luffy and Momonosuke.
Kaidou: "How did you survive!? Straw Hat!!
And who is this dragon!!? Introduce yourself!!"
Luffy: "I won't die no matter what!!!
Because I am the man who will become the Pirate King!!!"
Momonosuke: "My name...!!
My name is...!!
The man who will become the shogun of Wanokuni!!!
Yamato looks at the pink dragon, thinking about kid Momonosuke he met shortly before.
Kaidou: "Wororo so you are that kid!!
The world doesn't need 2 dragons!!! "
Luffy: You flew!!!
Luffy: That's it Momo!!
Luffy: Keep moving forward!!
Luffy: You're pretty fast! We should be there in no time!!
Luffy: Go Left!!
*Watermark is blocking the bubble*
Luffy: Alright!! We're here!! (lit. Alright!! We're at Onigahsima!!)
Luffy: I can see some shadows on the roof!!
Momo: The roof!?
Luffy: Dude, are your eyes even open!?
Momo: Don't be stupid!! Like hell I'd be able to fly with them open!!
Luffy: No not here!!
Luffy: This isn't the roof~!!!!
Skull Dome "Live Floor"
Scrub: Huh!? Kaidou-san!!?
Scrub: No it's not him!!
Queen: What the hell!? Another Dragon!!?
Hyo/Kawamatsu: A Dragon~!!?
Izo: What the hell is that!?