Giant insectoid aliens resembling cockroaches from a dying planet in "Space Hunter Nebula M" plot to colonize the Earth. The aliens assume the forms of dead humans and work as the development staff of the peace-themed Amusement park, World Children's Land, the centerpiece of which is "Godzilla Tower". The Nebula M aliens plan to use the space monsters Gigan and King Ghidorah, guided by two "Action Signal Tapes", to wipe out human civilization.