Potential Spoilers
After the Sinners defeat the Abnormality blocking the entrance to the 3rd Floor and descend, they are greeted by an unusually large population of maggots. Gregor begins hearing something, and opened the door to a containment unit following it. The team is greeted by a wave of golden light pouring from the room before being transported into the midst of a battlefield in the Smoke War.
Soon after they enter the battlefield, Heathcliff's coat is tugged from behind, and a young soldier named Tomah greets them. After a short conversation to dismiss Tomah, Gregor asks Faust about what exactly is happening. Faust replies that Gregor has resonated with the Golden Bough, and they have been transported into the fathoms of Gregor's ego.
After a vignette into Gregor's past: his operation for the bug arm by the Old G Corp. (specifically by a director of the corporation, Hermann) and his training to cut objects (a hanging apple) with his new arm, they were greeted by Tomah again, with the exact same opening conversation from him taking place. However, just after Tomah offered them a ride with his wing enhancements, Gregor spoke his heart that he neither wanted the enhancements nor the honor. At this, Tomah's enhancements mutated, indicating a breaking down in Gregor's psyche.
After another vignette into Gregor's experiences immediately after the war (and the collapse of the old G Corp.), Tomah emerges again, though this time he simply points upward (and saying, "I don’t want to die—") before being crushed to a pulp by giant hands descending from the sky. The Sinners proceed to run. However, as the team is tiring out, Gregor postulates that since this world is his heart and mind, they should not waste energy running away——Gregor himself has never been able to flee from the owner of these hands in real life. The Sinners decide to give the plan a try, and the descending hands take them out into the containment chamber of the Abnormality containing the Golden Bough.
The holder of the Golden Bough is an Abnormality that resembles a Golden Apple with thick, branchy stalks acting as arms and legs. After defeating the Abnormality with relative ease, Yuri approaches its "egg" to retrieve the Golden Bough. However, the Abnormality suddenly consumes Yuri, transforming into its second form: a rotten apple with a grotesque, monstrous head and long, lanky limbs——all made out of maggots. Gregor was quite shocked by the occurrence, and was further traumatized when the defeated False Apple used Yuri's head and voice in an attempt to lure the Sinners into giving it time and material to regenerate. The sight, along with Dante's calls for Gregor to cut the lure down, leads Gregor to a flashback regarding his arm growing uncontrolled and cutting down civilians after the war.
However, the False Apple's trick was foiled when Yuri's head was cut down by a team of strangers, led by the previously-mentioned Hermann, who then took the Golden Bough. Several of the Sinners recognized members of the rival team as family members or former comrades, and both sides exchanged tense chatter before Jia Huan clapped twice and all the Sinners lost consciousness.
Back on the bus, Vergilius chastens the Sinners for their failure to retrieve the Golden Bough. and Gregor decides to take up all the blame for the failed mission. He then hangs the gas mask worn by Yuri as a memento to her. Vergilius asks Charon whether it will interfere with her driving, and lets it be after receiving a negative response.