In this final episode of the Ultraman television series, a fiendish alien race, the Z-Ton Aliens, plots to conquer Earth. While plotting to cripple the Science Patrol Headquarters, they dispatch their giant insect-like monster, Z-Ton, to destroy it from the outside. After the Science Patrol destroy the Z-Ton fleet, Ultraman intervenes, but the monster proves to be more than a match for him! Will Ultraman, or the Science Patrol, be able to destroy Z-Ton? If Ultraman fails, what will happen next . . .