They still decide to advance though, and, in another hall, they find themselves in front of a gigantic, black Beyblade. To Gingka's dismay though, it only goes up to the third level : Merci voluntarily stopped it there, which means Doji had been planning their adventure in the castle all along. Eventually, they find a way they come across an elevator and decide to take it.
After being reassured, they decide to go further down the halls, but Merci blocks them by suddenly installing thick walls in their way. Kenta and the rest arrive at Gingka's side, asking him if he is all right.
Gingka tries to run faster and faster, but eventually Benkei helps him by launching his Dark Bull at the first end of the treadmill the latter breaks from the excessive wear and a 'hill' rolls towards Gingka it carries him on safe grounds and destroys the shooting machine. Only Gingka is left on the treadmill, and Merci decides to increase its speed a Beyblade-shooter machine also appears at the end of the treadmill and launches several Beys at Gingka, who quickly fetches his Storm Pegasus and launcher from its case to hit the Beys away from him. Next, Benkei trips as well but, having only just told Kyoya that he was keeping up fine, he decides to grab the end of Kyoya's coat, so they both get dragged backwards. Everybody tries to run faster in order to get off that trap, but eventually Madoka stumbles and hits Kenta backwards they both roll back to the beginning of the treadmill. Benkei realizes that they are on a giant conveyor belt. Strangely, they seem to never move forward in their race, even if they are in fact running as fast as they can. They however begin running down the multiple long halls.
Merci tells them that their road will be one full of obstacles because Doji does not really want them to step further into the building and discover more about Dark Nebula. The intelligent computer program mocks his previous naivety by saying "Tres bien!" again to fool him. After a while, Gingka begins to recall that voice from somewhere and he instantly figures out that Merci is the one speaking. They start hearing a voice from the speakers integrated to the small camera that is installed near the ceiling. Shortly after, they come to a big, posh room. The opening theme is "Galaxy Heart" (ギャラクシーハート, "Gyarakushī Hāto") performed by YU+KI, and the ending theme is "It Goes Over the Sky" (大空を越えてゆけ, "Ōzora wo Koete Yuke"), performed by Odoriba Soul.Gingka Hagane and his friends enter the Dark Nebula's Castle after completely destroying the front door. Two pieces of theme music were used for the opening and closing themes. See List of Beyblade: Metal Masters episodes for more information. They must then secure the spot of being the strongest Bladers in the world! When Gingka, Masamune, Tsubasa and Yu are chosen as the representatives of Japan, they won't hold anything back to become the world champions! Kyoya was chosen but turned the opportunity down, as he wants to battle Gingka, and joins the African Team along with Benkei who masquerades as the Masked Bull. The WBBA sponsors the new " Beyblade World Championships", a world tournament where four representatives from each country around the world gather and battle to become the world champions. Masamune is a new Blader who joins Gingka's group and will stop at nothing to defeat him. Gingka and his friends meet a new Blader named Masamune Kadoya.