The resemblance between Ultraman Geed and Belial has the public afraid of their new protector, making Riku question whether or not to use his new powers. Meanwhile, a mysterious woman with a sword is hot on the trail of marauding aliens.

Ultraman Geed runs into trouble when he is unable to defeat the mechanical menace, Darkclops Zero. Help arrives in the form of Ultraman Zero, but is he willing to see the son of his arch-enemy Belial as an ally?

Aizaki Moa is Riku's childhood friend, and an agent for the Alien Investigation Bureau, a group who monitors aliens living on Earth. When her latest case seems to be tied to the Little Star incidents, the two are reunited just in time for a giant monster to attack.

After Zero and Leito transform to help Geed, the mild-mannered family man suddenly finds the prospect of being an Ultraman exciting. Riku doesn't appreciate the insinuation that being a hero is all fun and games, so the two decide to trade roles to figure out who has it rougher.