After Yapool was defeated by Ultraman Ace, he went to recover in his own dimension. Alien Hipporit was one of a number of aliens who took advantage of the relative calm, and traveled to Earth to kill Ace and the other Ultra Brothers. Hipporit first appeared in a city, calling out to Ace to demonstrate his power to the Ultra by decapitating a giant statue of Ace before teleporting away. TAC soon found Hipporit in a remote area of the Japanese countryside and attacked him, but TAC's fighters were easily downed by Hipporit's strength. Eventually, Ultraman Ace appeared on the scene.

During the fight, Ultraman Ace and Hipporit were roughly matched in strength until Hipporit trapped Ace inside a glass chamber that appeared out of nowhere, where Ace was doused in an unusual liquid and gas inside the chamber. Then to everyone's shock, after a few seconds the chamber disappeared to reveal that Ace turned into a giant statue composed of bronze, but not before sending an Ultra Sign to the other Ultra Brothers (Ultraman, Zoffy, Ultraseven, and Ultraman Jack) who rushed to the scene. Shortly after discovering the bronzed statue of Ace.