A “wishing stone” that reacts to human brainwaves and changes into the holder's desired form, falls into the hands of a man called Onita and his will transforms the stone into the Kaiju Gango.

At first it obeys Onita’s and hides in a hotel, changing into a large humanoid form to scare people away. However, when Onita shares his desire for a “much bigger Gango”, it turns into a giant and is spotted in town. The hotel is destroyed in the transformation causing Onita to go into a coma, and Gango begins to rampage around town as if Onita’s soul has somehow transferred into the Kaiju itself.

When Ultraman came to fight it, Gango pretended to be weakened and used underhanded fighting techniques to waste time and avoid fighting Ultraman directly. In the end Onita wakes up from his coma in hospital and decides to take back his desires towards Gango, at which point it vanishes.