Short Story involving time travel, origin of man, and an ancient enemy

Question

I'm looking for a short story that involved:

• time travel;
• the search for the origins of humanity;
• an ancient enemy.

It was one of several short stories published in one of the monthly Amazing Stories that used to be popular so long ago (the 1970s for this particular tale).

The plot, inasmuch as I can recall, went along the following lines:

Historical anthropologists in the present use a time machine observe the very earliest homo sapiens. In their travels, they observe that although Homo sapiens are obviously related to our cousins in the evolutionary tree — Neanderthals and the like — Homo sapiens do not appear until much closer to the present than previously thought. They seem to just appear in the timeline all of a sudden.

As the search continues for the point in time when Homo sapiens makes their first appearance, the main character tries to understand why they would show up in suddenly in a rather short time frame compared to their evolutionary cousins.

The story ends when the main character realizes the obvious truth. Humanity did not evolve here. Humans were put here. A close friend of the main character reveals that it was all a test to see if Homo sapiens could grow and evolve to discover and understand their own origins.

Our progenitors had been locked in eons of war with creatures that can be described as Lovecraftian — immense monstrosities of unimaginable malice towards humans. It was a war our forebears were losing. They needed a way to wipe the slate clean, so to speak, and come up with a completely new source of strategies.

So they invented us. A small volunteer group of people had been stripped of everything, especially their memories. They were left on a fertile world with only the stone tools and basic implements to survive.

A small group of observers had also been planted on that world to document what happens. The main character's friend was the last of the observers. This observer was also immensely proud of humanity's ability to survive and innovate. In particular, they had been able to crack time travel, something the original species had never thought to try.

At the end of the story, the ancient enemy is out still there in the cosmos, waiting.

Answer 1

"Transfusion", a novelette by Chad Oliver, first published in Astounding Science Fiction, June 1959, available at the Internet Archive.

Wikipedia plot summary:

Anthropologists Ben Hazard and Ed Stone join a top-secret project which uses a time-travel device, affectionately known as "the Bucket" to return in time to observe human development throughout history. They are shocked to discover that, if they travel far enough into the past to research hominids such as Sinanthropus, they find nothing. There is no trace of humans or any related species in the deep past.

Hazard returns from a trip in which he proves that Sinanthropus did not exist in the time indicated by the age of the bones. He, Stone and their mentor, Franz Gottwald, discuss the problem. Gottwald, a by-the-book scientist, insists on facts, not speculation. They therefore decide on an exhaustive effort to discover when, and how, humans did appear on Earth.

Travelling back and forth in the past, Hazard and Stone happen upon an extraordinary event in France, over 25,000 years ago, near a cave where Cro-Magnon remains were found in their time. They see a gigantic spaceship land. Humans emerge, along with robots of various shapes and sizes. Using fantastic technology they shape the land into a primitive home, complete with artifacts such as stone tools. They deposit some apparently brainwashed humans wearing animal skins. They also bury objects in local caves. Hazard is sure that these are bones left for future generations to find.

Returning to modern times, they join Gottwald to try to solve the mystery. Clearly humans did not arise on Earth. The bones planted were probably genuine, but must have been brought from the real home of humanity. They can understand why humans might be seeded on another world, but not why the bones were planted.

Hazard takes a fishing trip to take his mind off the problem, hoping that an idea will occur to him. Remembering one of the chimpanzees used by his project trying to solve a simple puzzle, he decides that the whole thing is a gigantic experiment, a puzzle to be solved with some reward at the end. He also realizes that a necessary part of the experiment is an observer, someone who can monitor it. Such a person would want to get close to the time-travel project, and the best candidate is Gottwald himself, who came from Europe and never talks about his past.

Hazard finds Gottwald's house deserted. Entering, he finds a letter addressed to him, from Gottwald. It tells him that he has solved part of the puzzle, and for the rest he must press a hidden button and stand outside. He does this and is transported to the spaceship, still in orbit about Earth after 25,000 years. There he meets Gottwald and his wife, who are the last survivors of the people who came in the ship. Humans arose on a distant world, discovered faster-than-light space travel, carved an empire for themselves, and were then almost exterminated by the Enemy, a race of vicious monsters. So horrific are these creatures that they are part of human "racial memory", being the demons and dragons and other creatures out of nightmare.

The ship is one of four sent as a last desperate measure. The human race had to start again. It needed a "transfusion" of new ideas and ways of thinking, in order to survive the inevitable future encounter with the Enemy. Gottwald tells Hazard that his people never discovered time-travel. It may be the answer they were seeking. They wait for Ed Stone, who will surely solve the problem and join them. After that, they will begin the process of giving the ship's technology back to humanity, so they can be ready for the battles to come.

Excerpt:

Millions of years ago, on a world that circled a sun so far away that the astronomers of Earth had no name for it and not even a number, a new animal called Man appeared. His evolution had been a freakish thing, a million-to-one shot, and it was not likely to be repeated.

[. . . .]

Man discovered the Enemy.

It was not a case of misunderstanding, not a failure of diplomacy, not an accident born of fear or greed or stupidity. Man was a civilized animal. He was careful, reasonable, prepared to do whatever was ethically right.

He had no chance.

The Enemy—pounced. That was the only word for it. They were hunters, destroyers, killers. They were motivated by a savage hunger for destruction that Man had never known. They took many shapes, many forms.

Ben saw them.

He saw them rip ships apart, gut them with an utter ferocity that was beyond understanding. He saw them tear human beings to shreds, and eat them, and worse—

Ben screamed.

The Beings were more different from Man than the fish that swim in the sea, and yet . . .

Ben recognized them. He knew them.

They were there, all of them.

Literally, the Beings of nightmares.

The monsters that had troubled the dark sleeps of Earth, the things that crawled through myths, the Enemy who lived on the black side of the mind. The dragons, the serpents, the faces carved on masks, the Beings shaped in stones dug up in rotting jungles—

The Enemy.

We on Earth have not completely forgotten. We remember, despite the shocks that cleansed our minds. We remember, we remember. We have seen them in the darkness that lives always beyond the fires, we have heard them in the thunder that booms in the long, long night.

We remember.