4x19 - Bakugan Battle Brawlers

Dan heads off to fight Mag Mel, one on one and learn more about this Gate and Key he keeps talking about. When he reaches the inner chambers of Mag Mel's fortress, Mag Mel reveals that the Gate and Key is a mutated version of the Switch Code that Code Eve gave to Dan and Drago. Anubias and Sellon appear as Mag Mel summons several Mechtogan. The other Brawlers arrive but prove to be no match for the Mechtogan. So, Dan and Drago share their powers with the others, allowing them to summon their own Mechtogan. Spectra also arrives on the Vestal Destroyer and the Chaos Bakugan and Mag Mel are defeated. Dan realizes his mistakes with his friends and once again become the leader of the battle brawlers. Despite their victory Razenoid was able to collect the Gate, meaning that Mag Mel only needs the Key from Dan to achieve his goal.