When a rare species of butterfly is found in a mysterious valley in Japan, a pair of entomologists go to investigate and find more. They discover Varan, a giant monster, who decides to leave the valley and head straight for Tokyo.
In the midst of an attempt to take over his company, a powerhouse executive is hit with a huge ransom demand when his chauffeur's son is kidnapped by mistake.
After a meteorite unleashes a three-headed beast upon Tokyo, Mothra tries to unite with Godzilla and Rodan to battle the extraterrestrial threat.
