A young man named tE rU is causing a commotion in the city. Is he an alien? When he goes inside the mechanical giant Rudian it begins to march on the city. But after seeing tE rU heal an injured girl, Daichi unites with Ultraman X and attempts to stop Rudian, believing that it's not acting maliciously. With tE rU in custody, Xio examines Rudian, and a shocking fact comes to light. A dreadful beast is heading towards Earth, hungry for a secret contained within Rudian... and it's close.