From outer space

An elderly space veteran recounts Earth's first contact with enigmatic extraterrestrials detected via ultra-short wavelengths and telepathic reception. Leading scientists interpret the messages while the visitors, after disabling electrical systems and observing human customs, assess humanity through their own evolutionary perspective and swiftly assert control. Nations attempt resistance but are rendered powerless as the aliens impose a protective field, investigate human life, and reduce people to objects of oversight and display. The tale is framed as a cautionary recounting passed to later generations who must live under the consequences of that encounter.