In a church inside the Hanging Gardens of Babylon, Amakusa impales Kato Danzo several times with his Black Keys, eliminating her. Cinder appears and compliments his speed. Cinder draws her Black Keys and the two clash. Amakusa is shocked when Cinder draws more Black Keys and slashes him. He remembers he only gave her three, so she explains Archer taught her how to Trace to copy them. She offers a team up, saying if they are the last two, she'll give him her wish even if she wins. In her head, she asks Irisviel what her wish is, but she says it is a secret. Amakusa agrees, saying he fights for someone else's wish as well. Cinder asks who it is, but he says he wouldn't want to embarrass her. Glynda and Medea are watching the Round in the staff lounge when Semiramis blushes and drops her cup. Cinder says she would like to take down Ruby Rose first, so they set out to find her.
Ruby, Lobo, and Enkidu make it to the roof and find the beautiful gardens the structure is named for. Ruby is amazed and points out she never saw the gardens while watching the previous rounds, so Enkidu points out people hardly last long enough to reach the roof, plus the roof is dangerous because it is easy to get knocked off. A storm of rose petals happens and Nero appears in front of them. Brandishing a rose, she declares at last, she has found Ruby Rose, her arch enemy, only to get the wind taken out of her sails when Ruby doesn't know who she is even though they had met before. Nero introduces herself and says she is the only one who should have power over roses. When she wins, her wish will be to force Ruby to switch Classes until she loses her ability to make rose petals. Ruby refuses, saying if that is possible, then she might also lose her Reality Marble, which would separate Lobo and Blanca.
Nero says that is not for Ruby to decide and starts a chant, but part of the roof explodes and Cinder and Amakusa arrive. They say at last they have found Ruby. Nero yells at them for interrupting her, but they ignore her, pissing her off. Ruby becomes scared of Cinder due to remembering the time Cinder and Archer kicked her and Astolfo's butts. Irisviel, Illya, and Chloe are watching Cinder on a screen and they notice Cinder is pissed off at Ruby. Chloe suddenly clutches her stomach in pain, but she says it is nothing.
Cinder summons her glass swords and Nero summons her flaming sword, then they lunge at Ruby at the same time. Lobo summons Violet Gibbous and blocks Nero, while Enkidu blocks Cinder with his chains. As they take each other on, Amakusa attacks Ruby. He uses Glyphs to control his Black Keys and make them fly at unexpected angles, but Ruby blocks them due to being experienced with Weiss' Glyphs. Amakusa summons a katana and belittles the weapons of Ruby's homeland, saying his weapon is for killing, while their shape shifting weapons are just for showing off. Enraged, Ruby attacks him and says their weapons are for killing Grimm just like his, and she will not tolerate anyone disrespecting them. He smiles and says she is interesting, then they clash some more.
Cinder dodges Enkidu's seemingly endless chains and asks for advice. Irisviel is distracted, but says the chains are unbreakable, so if she is caught, game over. Cinder detonates her swords to blind Enkidu with the smoke, then forms her bow and fires glass arrows. The chains block them and they shatter, but Cinder reforms them in midair and one hits him in the head and explodes. He emerges from the smoke bleeding from the head. Nero fends off Lobo and chants, "See my talent! Hear the thundering applause! Thus praise! Golden Theater! Aestus Domus Aurea!" The fighters suddenly find themselves in a huge golden theater with red carpets and rose petals everywhere.
Everyone except Nero starts losing strength and can barely stand. Nero says this is her Reality Marble, where her opponents' strength is drained and added to her own. She used it to win Grand Order last year, and her wish was to make it so spectators would be able to see inside when she uses it in another Grand Order. Chloe comments Cinder might be doomed, but Irisviel reminds them Nero can only use it for ten minutes, so Cinder still has a chance. Chloe clutches her chest and is breathing hard. Worried, Illya asks what is wrong with her. Again, she says it is nothing. Under her breath, she hopes it is nothing.
Nero attacks the others and gets several hits in on all of them, effortlessly outspeeding and overpowering them, before hitting them with a fire blast from her sword. She assumes she has won, but Cinder, her clothes burnt, fires an arrow that she blocks. Cinder says this Reality Marble is a joke. Nero asks what she is talking about, then Amakusa, his shirt gone, sneak attacks and cuts her cheek. They say Nero has no skill and a simple power boost is meaningless against true fighters. Nero says it doesn't matter as long as she wins. They attack her, and despite her strength advantage, overwhelm her with their superior sword skills. Nero slices through Cinder's sword, but Cinder simply stabs her with the stub while she is gloating. Back in the staff lounge, Glynda sighs and comments she had tried to get Nero to address her lack of skill. Meanwhile, Semiramis gawks at Amakusa's shirtless body.
Enkidu shielded Ruby and Lobo from the fire blast with his body, saying they are a team. He collapses and Ruby and Lobo are ready to collapse too from the energy drain. Ruby gets an idea. Nero is still getting pushed back by Cinder and Amakusa. She sees Ruby meditating and angrily runs over to strike her down. Ruby opens her eyes and releases silver light to take them to the white void. Cinder explains to Amakusa that this is Ruby's Reality Marble. Amakusa thanks her because now that they are out of the Golden Theater, their strength is returning. Enkidu asks how she knew that would work, and she says she had seen it before, when Iskandar overwrote her Reality Marble with his own. Ruby then almost throws up from exhaustion.
Nero can't believe Ruby has a Reality Marble, but mocks it as it is empty. Then a boy in a white robe and shoes walks up. Shocked, she calls him Hakuno. Amakusa tells Cinder that he is Hakuno Kishinami, Altera's boyfriend, then gets confused because Hakuno is dead. Cinder tells him to focus on taking out Ruby. Nero asks how Hakuno is here, so Ruby explains her Reality Marble lets people see people they have lost. Nero says she was in love with him, but never told him because he was Altera's boyfriend, then he got killed by the Grimm. Ruby says now she can, but Nero roars that he's not real and that Ruby is a monster for playing with her emotions like this. She attacks Ruby, but Summer Rose appears and blocks the strike with her scythe.
Cinder is a little scared of Summer, but reminds Amakusa that if they take out Ruby, the Reality Marble will fall. They charge, but Amakusa's path is blocked by Blanca and Wolf. Sakura Matou, wielding her U-headed spear Trishula, blocks Cinder's path, causing her to get angry and summon a spear of her own. Nero clashes with Summer, but Summer has the advantage of being able to sink into the floor to avoid her attacks, then slashes Nero. Enkidu is amazed by Summer's skill. He turns to see Amakusa fighting Blanca and Wolf. Like Summer, they can sink into the floor to avoid attacks. Enkidu tries to help them, but is too injured. Amakusa almost manages to stab Wolf, but Blanca bites his arm. Ruby watches Nero and Summer's fight and says she missed watching her mother fight.
Cinder and Sakura clash. Sakura disorients Cinder with a sonic attack and then fires lightning from her spear, but Cinder distracts her by detonating her spear, then shoots her in the heart with an arrow. Sakura doesn't bleed, but she falls to her knees and drops her weapon. Cinder says she killed BB and now she will kill her, all for Archer, so that he can finally move on. To her surprise, Sakura gives her a warm smile and says something, but no sound comes out. She turns into a cloud of white dust that washes over Cinder. Cinder screams in pain and vomits something black. The tattoo on her back disappears. Cinder gets up and wonders what just happened. She read Sakura's lips and wonders why she said, "Thank you."
Amakusa fends off the wolves and says he has had enough. He dismisses his sword and holds up his hands. His right hand forms a black and purple energy ball and his left hand forms a white and blue energy ball. He chants, "Heaven's Feel begin. An end to all things. Twin Arm Big Crunch!" He throws the balls together and they turn into a black hole. Blanca and Wolf run away, but Hakuno gets sucked into it. Enkidu and Lobo are too weak to move, and Enkidu screams for Ruby to get them out of there. Ruby panics, but Summer steps up and fires silver beams from her eyes that clash with the black hole. Ruby screams for her, but the silver light expands and covers everyone.
Ruby, Enkidu, Lobo, Cinder, Amakusa, and Nero find themselves back in the Hanging Gardens' roof. Ruby hears Iskandar's voice asking her what happened as her Reality Marble was active for eight minutes. Ruby wonders what happened to her mother. Enkidu can communicate with animals, and Lobo tells him Summer, Blanca, and Wolf are fine inside the Reality Marble, but Sakura and Hakuno are gone. Nero suddenly roars that she will make Ruby pay for everything, but Cinder throws an exploding sword that knocks Nero off the roof and eliminates her, saying it's about time she shut up. Amukusa says he's out of energy and so is Cinder. Cinder asks Irisviel to use a Command Spell to heal her, but she doesn't answer. She panics and asks what is wrong. After a few seconds, Irisviel, distressed, tells Cinder she needs her back now. Cinder says she can still win, but Enkidu and Lobo suddenly attack her. Ruby attacks Amakusa who can barely lift his sword. Ruby pauses and says it doesn't feel right to fight him in this state. He lectures her that in a real fight, showing mercy can get you killed. He attacks her with Glyphs, then lands a punch that breaks his arm, but it also breaks Ruby's ribs and knocks her off the roof. Just in time, Ruby fires Crescent Rose so the recoil brings her back and she manages to grab the outer wall of the Hanging Gardens.
Lobo tackles Cinder off the roof, but she uses him as a springboard to grab the edge. Lobo is teleported to Iskandar's room, who pats him and says he did well. Enkidu gathers chains and attempts to knock Cinder off the roof, but Amakusa stabs him in the back. Enkidu comments that was anticlimactic and falls off the roof. Amakusa attempts to help Cinder up, but Enkidu throws a chain that wraps around his leg and pulls him off the roof. Enkidu and Amakusa are both eliminated. Cinder pulls herself up and sees Ruby managed to climb back to the roof. Cinder only has enough energy to summon a single sword. They charge at each other, but Cinder is teleported away.
Cinder finds herself back in Irisviel's room and demands to know why. She sees Irisviel and Illya kneeling next to Chloe, who is on her back covered in sweat and screaming in pain. Cinder is horrified and asks what is wrong. Irisviel apologizes for pulling her out, but she couldn't concentrate with Chloe in this condition. Cinder notices the tattoo on Chloe's stomach is glowing red, and realizes with dread that something has happened to Archer.
Ruby asks what just happened. Stunned, Iskandar says Cinder's sponsor teleported her away with a Command Spell, which means the winner of Round Four is Rider: Ruby Rose, but they don't know why. Suddenly, a huge explosion and a pillar of darkness appears in the distance. Ruby and Iskandar are horrified when they realize it came from the fishing town that Blake, Ren, and the others were helping to fix.
