Full summary, thanks to redon from Arlong Park Forums.
Chapter 1,020: "Robin Vs. Black Maria".
In the cover, Denjiro (as Kyoushirou) is spleeping with a samurai Mink (he seems a leopard). He's dreaming that he's eating a big tempura, but he's eating his wig while he sleeps.
Chapter starts on the top of Onigashima's Skull Dome, Kaidou is talking.
Kaidou: "Dog Dog Fruit, Mythical Type, Model “Ooguchi no Makami” (Large-Mouthed Guardian Wolf)!!!
It's a valuable Mythical Beast and the deity protector of Wanokuni!!
I didn't expect that someone who call herself “Oden” could eat it!!"
Kaidou hits Yamato with his kanabo.
Kaidou: "Orochi had a talent as a terrible dictator.
That's why this country is now a weapon factory.
I want you to rule the country and keep in running for my sake!!"
I will free the country and the samurai!!"
Yamato uses a new attack called “Namuji Hyouga” (無侍氷牙 - None-Samurai-Ice-Fang) shooting a big flame from his mouth to Kaidou. While attacks, Yamato remembers Oden's words (“Open Wano's borders!!”). Kaidou uses his “Bolo Breath”, both attacks clash in a huge explosion.
Kaidou: "I'm not going to allow it, Yamato!!"
Cut to the “Great Banquet Hall” in the 3rd floor. We see that Robin is in front of 3 people who are very important for her: Nico Olvia (her mother), Dr. Clover and the giant Jaguar D. Saul. The three of them are very happy to see Robin and call her to come to them. Robin is very happy too and runs towards them while Brook yells at her not to do it.
Just before reaching them Robin stops, she is disappointed by the obvious trap they have tried to set. She then uses a new attack called “Tres Mano: Freesia” to eliminate the illusions and hits with a giant slap on the chin of those who were posing as them.
We discover that they were 3 of Black Maria's subordinates: “Nure Onna” (user of hognose snake SMILE), “Tenjō Sagari” (user of white snake SMILE) and a female Numbers called “Kunyun” (Number 9). Black Maria used her “Illusion Mist” (幻霧) on them to pose as Robin's loved ones. Despite Robin's attack, Black Maria's subordinates are still on their feet chasing Robin and Brook down a hallway.
Black Maria destroys part of the room and also chases them. Robin asks Brook how he wasn't affected by Black Maria's trap, Brook tells her that he's been seeing illusions in the mist for 50 years in the Florian Triangle, so no one can fool him with tricks like that. Robin laughs and mentions how the two of them are similar because of all the trauma they have been through in their lifes.
Black Maria uses “Furisode Wanyūdō” (振袖輪入道 - Long-sleeve Kimono Wanyūdō) and attacks them with her flaming Wanyūdō. We discover that the Wanyūdō is actually one of her subordinates, who ate the "Pug SMILE" and became a human-face dog. His dog body is running at the center of the wheel like a hamster, producing the flames.
Black Maria jumps onto the ceiling and manages to get in front of Robin and Brook, then she uses her Wanyūdō again to burn the floor of the room. Robin and Brook jump to avoid the flames, then Robin uses her "Spider Net" to create a web and hold on to the ceiling carrying Brook in her arm.
Brook's soul then leaves his body and attacks Wanyūdō with “Cold Soul” (コールド魂) freezing him (Wanyūdō falls off the wheel). Black Maria is furious and attacks with her rod the area of the ceiling where Robin is clinging. However, Brook returns to his body and uses his attack "Soul Parade: Eisbahn" (Soul Parade: Ice Burn) to freeze the ground and put out the fire, so Robin lands safely.
Black Maria and Robin are face to face. Black Maria mocks Sanji for crying for help while Robin remembers with a smile Sanji's words (Help me!!! Robin-chan!!!). Black Maria continues.
Black Maria: "And he's the Number 2 of your group?
He became a laughing stock of Onigashima and let you fall into enemy's hands!!
Your nakama must have abandoned you!!"
Brook laughs looking at Robin as she tells him that she will take care of Black Maria. Brook tells her it's OK, he will take care of the other Black Maria's subordinates (the 2 women and the female Number from before). Robin answers Black Maria.
Robin: "Sanji is a kind person.
You don't need to understand what it means for him to depend on me.
He is the one fit to be “The wings of the Pirate King”!!!
“Gigante Fleur” (Giant Blooming - 巨大咲き (ヒガンテ・フルール))!!!"
A giant version of Robin blooms behind her...
Cut to Tokage Port in Wanokuni, Shinobu and Momonosuke meet up with Luffy and the Heart Pirates. Luffy has eaten all of Heart Pirates supplies but they aren't enough so he still can't move.
Momonosuke is crying about Kinemon and Kiku, Luffy tells him to stop and to worry about that later, since he's still the general of the samurai. Shinobu scolds Luffy because he's being too harsh with Momonosuke.
Caribou is watching them from beind the rubble. He's worrying whether Luffy can win, since if Luffy can't, he won't be able to leave Wanokuni. Luffy raises his right arm and points to Onigashima's island in the sky.
You have to fly up to the island and take me with you...!!!"
End of the chapter.