SOS: There's a war between two planets called Mechtania & Ceros. The leader of Ceros sends three of Ceros' young soldiers (Courtney, Darren, & Bruce) to find the Battle Brawlers on Earth. On Earth, Dan, Jake, & Shun are playing Bakugan in the football field when they're greeted by Courtney, Darren, & Bruce. The Cerosian visitors tell them that their home planet is under attack by the Mechtaniums. The brawlers agreed to help them, so Courtney, Darren, & Bruce takes thems to Cerosian Headquarters. At Headquarters, Courtney gives Jake Subterra Cobrakus & Shun Ventus Taylean. But Dan doesn't need a new Bakugan saying that Drago has always been his Bakugan partner & always will be during battles. Courtney lets Dan keep Drago although she's unsure is Drago's strong enough against the Mechtogans, transformer-like Bakugan used by the Mechtaniums. A battle against the Mechtaniums begins, so the brawlers start fighting alongside the Cerosians. Although they fight hard, the brawlers lose & Jake, Shun, Courtney, Darren, & Bruce mysteriously disappear while Dan is all alone & injured...
Captivity: Dan finds himself in a Mechtanium prison, where he sees Drago who looks like he's being tortured. Dan tries to help his friend, but he feels weak from the battle & passes out. A few hours later, Dan is waken up by Drago, who's in a new ball form. When Dan asks Drago what happened to him, a non-Mechtanium named Morgan tells Dan that he changed Drago's ball form (but not his Bakugan form) in order to save his life. Morgan then explains that the Mechtaniums have conquered many planets in order to show the universe that they're the most powerful planet. Then Mechtaniums come in & tells Dan that they want him to make a battle tank for them. Dan refuses, which causes the Mechtaniums into torturing him. Minutes later, the Mechtaniums tell Dan that they have all the equipment he needs to build the tank. They then tell Dan if he finishes their it perfectly, they'll set him free. Dan finally agrees to do it, but instead of building a battle tank, he & Morgan are building armor for Drago.
Dan's Escape: The Mechtaniums are getting impatient with Dan & Morgan. Their leader, General Rex, asks Dan why has he failed him. Morgan tells Rex that they're working hard, but Rex doesn't believe him & tries to torture him by putting a piece of coal in his mouth. But Dan attempts to spare Morgan's life by telling Rex that he's needs a partner in order to build the battle tank faster. Rex gives Dan & Morgan two weeks to finish the battle tank. Dan & Morgan continue to work on Drago's armor. After finishing it, Dan helps Drago put on his armor. Rex sends soldiers to check on Dan & Morgan, but they're suddenly killed by a bomb that Morgan made. Rex sends in more soldiers, so Dan sends Morgan to fight off the Mechtaniums. Morgan does so, but he's quickly taken by the Mechtaniums. The soldiers look for Dan, but Dan fights them off with a weapon Morgan gave him. Dan then finds Morgan dying. Before he dies, Morgan tells Dan not to waste his life while fighting the Mechtaniums. After Morgan dies in Dan's arms, Dan tells Drago that it's time to kick some Mechtanium butt. Dan & Drago are the surrounded by the Mechtaniums. The Mechtaniums start to attack Dan, but Drago uses his powers to protect Dan. Dan then throws Drago, & Drago reveals his new form: Meta Dragonoid. A battle begins, & the Mechtaniums are quickly scared of Drago & retreat. Dan & Drago then fly away with Drago's new built-in jet pack, but then something goes wrong with Drago & he reverts back to ball form. After surviving the crash, Dan & Drago go around the dunes until they see the other brawlers flying around, looking for them. Dan calls for his friends & they rush to him & hug him, showing him that they're happy to see him again.
At Cerosian Headquarters, Courtney tells Dan that he & Drago needs to be taken to see a doctor, since there could be something wrong with him. Dan argues with Courtney that he & Drago have been in the Mechtanium prison for only four months, & says that he wants something to eat first & have a confrence with all the Cerosians.