After a meteorite unleashes a three-headed beast upon Tokyo, Mothra tries to unite with Godzilla and Rodan to battle the extraterrestrial threat.
A floating amorphous life-form descends from the atmosphere to consume carbon in the form of diamonds.
The film consists of re-edited material from the original television series Ultraman. Episodes 1, 8, 26, and 27 were used for the film. They were narrated by Hikari Urano as an "Ultraman Documentary". Allegedly only one new scene was shot, and that some parts of the movie where shot in black and white for unknown reasons. The movie screened at the same time as the Toho movie King Kong Escapes.
