The Master Key that Gustang gave to Baam reacts with the door to the Hidden Floor, pulling in all present except Karaka and Yuri. They wake up separated in a void, but are soon attacked by mechanical robots. Baam wakes up separated from the group, but Androssi quickly uses Bong Bong to teleport herself to him. The Scale of the Past soon appears before each group and reveals they're in the Hidden Floor, and will tell them their destination after the void as well as generate their Sworn Enemies, memories of the past designed to challenge them. The scale sends Wangnan to The King's Cradle. Because Baam has no past, he and Androssi are sent to a quarantine zone. Khun and Hockney fall to Rak's location at the beach but are eaten by an eel, and Baam and Androssi are saved from a quarantine trap by the data of Yu Han Sung.
The Hidden Floor's origin is then revealed: A mirror that could store data of regulars' present selves was constructed by The Workshop and gifted to Zahard, who placed it in the final room of the Hell Train. His companions and others who cleared the train stored their data as well, constructing their own society within. Witnessing this development, the workshop scientist protected it by placing a spell over it that would cause those who revealed its details to forget their experience.
The data of Regular Yu Han Sung reveals he knew Baam and a Princess of Zahard would appear in quarantine, and tells Baam and Androssi to follow him further into the zone. He knows they seek to meet the data of Zahard, and agrees to help them find him. Meanwhile, Rak reunites with Aguero and meets Hockney in the eel, explaining he's still alive. He attacks the eel from within to force it to spit up the regulars, and the three are brought back to shore by Mi-Eum and Goliath. She introduces herself as a guide to the regulars and explains how most begin their journey on the floor here. They head towards the nearby town, and she tells them that they must watch out for their sworn enemies, designed to constantly return and prevent excess influence by the regulars on the floor.
Deep in the quarantine area, Baam's sworn enemy is generated: himself. The enemy attacks and Hansung prepares to kill him with a trap, but Baam saves him, insisting on fighting himself. He tries to persuade his enemy to give up, but knocks him out after he fails. More soldiers attack and the regulars escape, but Baam saves his sworn enemy from an explosion. His sworn enemy tries to continue fighting, but is tranquilized by Batis.
Mi-Eum explains to Khun's party that there are different stages of the Hidden Floor, and shows them a meter that measures their good and bad actions. In the distance, they notice the statue of the Giant and the Fruit of Good and Evil. If they commit evil deeds, their sworn enemy will pursue them and the Giant will awaken and eat the fruit to punish them, and if they do good, they can eliminate the Fruit of Good and Evil and move to the next stage. They also learn that the fruit acts as a quarantine zone. They arrive at the Town of the Wandering Minstrel, meeting Boro and Sachi. The village head, Dee, gives them the mission to defeat the evil within the Fruit, which they accept. She sends them on a quest to defeat plant monsters to continue their progress. They quickly succeed, and Mi-Eum then explains they'll soon face a stronger enemy from the Big Breeder, who acts as a caretaker and functional god of the floor.
Batis and Hansung greet each other, and the former leads them all back to the seed shelter within quarantine. He explains that the quarantine area is inside the Fruit of Good and Evil, and he and other Data Humans have been trapped inside, unable to escape. Most were condemned for speaking out against evil deeds committed by the Big Breeders, including Batis himself. He reveals he was the previous Wandering Minstrel, but was locked away for spreading songs of the Big Breeders misdeeds towards data humans and inciting rebellion. They mutilated his mouth so he couldn't sing, turned his daughter into a mute, and placed him in quarantine. In another location, a Big Breeder assures data Zahard he will protect the floor from the new regulars, revealing Rachel sleeping behind him.
Hansung reveals they can escape before the grand quest is cleared if they break through a door at the end of the labyrinth inside the fruit, but none of them are strong enough to open the door. Baam says they need to hurry before Aguero's team can clear the quests. Aguero, meanwhile, summons a high-level quest and begins fighting Octopus Kim with the others. The Big Breeder interferes and turns up Kim's power to kill them, but they defeat it by trapping the octopus in a large tube and restrict it with Sachi's vines. At the same time, Baam's enemy awakens and soldiers attack the shelter. Endorsi teleports them to safety, and Hansung destroys the Seed with his explosives. Batis convinces Hansung to take Bam and Endorsi and leave the others behind, and Hansung gives Baam the task of defeating the Big Breeders, one of whom has just appeared in the village.
Chung, the big breeder, greets Aguero's party and reveals the grand quest to defeat the Mother Long-Tailed Tit. He purposefully weakens it to grant them an easy quest, telling them it's a reward after a difficult fight against Kim while truly intending to rush them past the stage and kill those trapped in the Fruit. Khun hesitates for fear of a trap, giving Baam's side time to rush through the labyrinth and defeat the soldiers in their path. They soon reach the door, and Baam easily breaks through it to free his companions. Inside the fruit, however, a sworn enemy reveals himself and kills the data humans who stayed behind.
Chung, shocked at the news of their escape, awakens the giant to defeat them. They fight and defeat the giant, then quickly make their way to the village. Batis confronts Chung, and Baam reunites with Rak and Aguero. Chung sends the soldiers after the data escapees, but they are quickly defeated. He then releases a villain in one of the Mother Tit's eggs, distracting Aguero's group. Baam attempts to attack Chung while he lectures Batis, but Chung easily blocks his attack. Androssi assists Batis in landing a blow on Chung, but he appears unharmed and invincible, stabbing Baam in retaliation. He then takes Dee hostage, revealing her true identity as Rose, Batis' wife. He orders her to die for him and is about to kill her, but Chung uses her body as a shield to block Batis' bullet instead, dying in the process. Before he can fight, Rachel awakens and removes Chung's virtual helmet, removing him from the Hidden Floor.
See More Images here: The Hidden Floor (Arc Images)