Daichi Ozora, a young member of the Xio defense team, discovers a mysterious artifact called the Spark Doll. This Sparks Doll has the power to summon ancient Ultra Warriors. Daichi's discovery coincides with the sudden arrival of a threat from space—an enormous, destructive beast unleashed by an alien villain. As chaos erupts on Earth, Daichi accidentally bonds with a digital deity known as Ultraman X, enabling him to transform into the giant hero and combat the monster menace. The bond between Daichi and Ultraman X grows stronger as they face off against various creatures wreaking havoc on the planet, elevating each other’s abilities and forging a unique alliance.

As the battles intensify and the stakes rise, Daichi and Ultraman X must uncover secrets concerning both Ultraman X's past and the true intentions behind the alien villain’s incursions. Alongside his Xio team members—including the tech-savvy Asuna and brilliant scientist Wataru—they gather every resource to fend off increasingly powerful adversaries. All the while, Daichi learns valuable lessons about trust, bravery, and the essence of being a hero. Facing monumental challenges and personal dilemmas, Daichi's resolve is tested like never before, leading to unpredictable twists that culminate in a high-stakes showdown to secure Earth’s future.