Harrison, Suzanne and others in “Unfinished Business”

35 years ago, a great invasion force of aliens nearly obliterated mankind in an all-out attack from the stars. They came here in these spaceships, and they fell from the sky dead... or so we all thought. Earth was saved from interstellar conquest by the presence of common bacteria found on this planet, but they were not dead, as my adopted father, Dr. Forrester, tried to warn everyone. They were only asleep. Dr. McCullough?

They are capable of inhabiting human bodies, a perfect cover which allows them to roam our cities undetected, unnoticed.

We are at war, gentlemen, and we had better win.

There won't be any second chance.