In the present day, Ultraman Mebius protects the Earth. But the most powerful aliens that have ever battled the Ultraman Brothers have plans to release U-Killer Saurus and conquer the world. When the aliens launch their combined attack, even Ultraman Mebius cannot defeat them. Can the Ultraman Brothers regain their powers to help Moebius fight the aliens? Will they succeed in their plans to revive U-Killer Saurus?