Even among the most changeable of living things, Man is quicksilver-more chameleon-like than the chameleon, determined to survive, no matter what the cost to others... or to himself.
"A flying saucer has landed in a remote part of the United States and wiped out a military patrol sent to investigate.
Falsely believing that the saucer contains nuclear material, the authorities decide on a wild scheme: they recruit Louis Mace, a disaffected CIA agent, to infiltrate the ship.
He also begins to question his allegiance, and eventually sides with the aliens, finding out that they're benevolent and have no desire to come in contact with humans in any way, being simply stranded on Earth after their ship's engine broke down.
Torn between his desire to be free and his loyalty towards his superiors, Mace first reacts aggressively, killing one of the two aliens, but he eventually realizes the cruelty of his act and feels remorse for showing these harmless visitors what dark instincts inhabit the human nature.