Looking for the Road-Poneglyph, Brook managed to get into the treasury after Pedro played bait and managed to distract Baron Tamago and other guards, leaving only a few guards posted inside. However, Charlotte Smoothie was also still on site and although Brook had ruled her out, she wasn’t worried as there was only one entrance/exit. Unfortunately for him, however, Big Mom was also informed of the intruder and made her way to the treasure room.
When the Empress finally caught the intruder, she was impressed by him and wanted him for her collection, whereupon a fight ensued. However, when the Straw Hat Musician found himself motionless in her hands a short time later, she attested to his extraordinary strength and impressive fighting skills, but she also said that he simply didn’t stand a chance against her three homies created from her soul. The fight itself was not seen in the manga, though it did turn out that Brook was able to make a copy of the poneglyph undetected and hide it in his skull. So, despite his defeat and subsequent capture, the mission was, in a sense, a success.
When the Empress came upon the intruder, he was determined to take the fight to her to make a copy of the Poneglyph. Brook jumped onto the railing and ran around Big Mom to find an open spot and when he got behind her, he attacked with Gavotte Bond Avant. However, she had seen through this and electrocuted him through Zeus. Prometheus then went on the offensive as well, and while the skeletal human dodged the flames, he countered with Swallow Bond en Avant, but he was unable to land a hit and was caught by the flames himself.
He picked himself back up, however, and promised Big Mom he had another ace up his sleeve. With a rock ballad he tried to release the souls from the homies, but this had no effect on Prometheus, Zeus and Napoleon, as they were created directly from Big Mom’s soul. As a result, the Empress only wanted him more in her collection and exposed Brook to the flames and shocks of her homies, causing him to go down. However, he was able to pick himself up once again and took advantage of a moment of inattention as Big Mom argued with Prometheus and Zeus to attack the Empress head on.
This, in turn, Napoleon saw through and delivered a blow in his sword form, causing the Straw Hat Pirate to go down once more. Despite this, he righted himself one more time and emphasized his motivation in the conversation that followed. Determined, he attacked the empress, managing to dodge the homies’ attacks and attack her head-on, but his attack did not go through his opponent’s tough skin. She then grabbed him and threw him across the room against a wall. With his last ounce of strength, he attacked Prometheus with Aubade Coup Droit, but could only give him a gash and then cashed in on a huge punch from the Empress. Brook was now finally defeated and was added by Big Mom to her collection. Unrecognized, however, he was able to make a copy of the Poneglyph, making the mission a success despite his defeat and subsequent capture.