It is set during the last ice age as a modern man is living among a small community of early humans and is told to kill one of the last neanderthals as a test to see if he is really human or a savage.

The only other thing I remember the time travel device is referred to as a rainbow.

  • 1
    Does it have robots? :) Commented Mar 25, 2012 at 13:36
  • Hm. Project Rainbow was the apocryphal Philadelphia Experiment. Commented Mar 25, 2012 at 15:17
  • 2
    Is it possibly the same as this question? Commented Mar 25, 2012 at 15:23
  • DVK No it does not, Mark, the story implied that "The Rainbow" was just a colloquial name for the method of time transport and sadly thats not the story I'm looking for.
    – Vladimir
    Commented Mar 29, 2012 at 7:02
  • I remember this story, and If I could add some of what I remember: they early humans had several religions, built homes out of mammoth bones that were mechanically intricate and robust, when asked to kill the Neanderthal he realizes he cannot, and passes the test of the early humans for being compassionate. This story is from the 80's or early 90's at best...
    – Gio
    Commented Jul 8, 2018 at 22:19

6 Answers 6


Pretty sure this is House of Bones by Robert Silverberg. It is a short story, first published in the 1988 anthology book, Terry's Universe.

This review of the anthology book, Dangerous Dimensions, offers an overview of the plot, noting that the protagonist winds ups stuck 20,000 years in the past, where he's taken in by a tribe, but also asked to kill a lone man wandering the outskirts of the tribe's territory.

Gebravar in "House of Bones" travels back 20,000 years in time to visit our ancestors. It was meant to be a two-week excursion, but it appears that he's stuck in this era. Luckily, a tribe grafts him in, and he has a home with some safety. However, the tribe sends him out to kill a "ghost," a tribe-less man who is wandering on the outskirts of the tribe. Gebravar isn't sure if he can do it.

Reading through the story itself, the protagonist was sent back in time from the year 2013 by a mechanism called the Zeller Effect rainbow.

I was supposed to be here just four days and then the Zeller Effect rainbow would come for me and carry me home. Of course within a few weeks I realized that something had gone wonky at the uptime end, that the experiment had malfunctioned and that I probably wasn't ever going to get home. There was that risk all along. Well, here I am, here I stay. First came stinging pain and anger and I suppose grief when the truth finally caught up with me. Now there's just a dull ache that won't go away.

It also transpires that the "ghost" or "Scavenger" he's asked to kill is actually a neanderthal.

In early afternoon I stumble across the Scavenger Man. It's pure dumb luck. The trail has long since given out -- the forest floor is covered with soft pine duff here, and I'm not enough of a hunter to distinguish one spoor from another in that -- and I'm simply moving aimlessly when I see some broken branches, and then I get a whiff of burning wood, and I follow that scent twenty or thirty yards over a low rise and there he is, hunkered down by a hastily thrown-together little hearth roasting a couple of ptarmigans on a green spit. A scavenger he may be, but he's a better man than I am when it comes to skulling ptarmigans.

He's really ugly. Jeanne wasn't exaggerating at all.

His head is huge and juts back a long way. His mouth is like a muzzle and his chin is hardly there at all and his forehead slopes down to huge brow-ridges like an ape's. His hair is like straw, and it's all over him, though he isn't really shaggy, no hairier than a lot of men I've known. His eyes are gray, yes, and small, deep-set. He's built low and thick, like an Olympic weightlifter. He's wearing a strip of fur around his middle and nothing else. He's an honest-to-God Neanderthal, straight out of the textbooks, and when I see him a chill runs down my spine as though up till this minute I had never really believed that I had traveled 20,000 years in time and now, holy shit, the whole concept has finally become real to me.

In the end...

... the protagonist realises he can't go through with killing the neanderthal, and returns to the tribe with the neanderthal in tow. He anticipates that the tribe may decide to kill both him and the neanderthal, and he's willing to fight them to the death if it comes to that. It turns out however that the tribe members are pleased to see that he didn't kill the neanderthal. He concludes that the whole thing was a test to see how civilised he actually was.


Lester Del Rey wrote a book "Tunnel Through Time" where the time machine created a tunnel that was visible as a rainbow ring. The first man through, "Doc Tom", did not come back and sons of Sam Miller, the scientist who made the tunnel, and of Doc Tom, go back to find him - to the age of the Dinosaurs

It turns out there are some glitches - the tunnel entrance moves somewhat each time, and sometimes appears on water where it can't be got at. The boys find Doc Tom, but when the rainbow ring meets the land it comes in next to a brontosaurus who steps into it and gets chopped up, damaging the equipment.

The damaged ring can only take some of them, part way back, so the kids go ahead, but land in the Ice Age and aren't ready for the blizzard. They find a cave and the shelter gets warm when a mammoth sleeps across the entrance. They nod off, and almost freeze to death when the Mammoth leaves. Doc Tom finds them first.

The next jump goes to an interglacial time, and they meet primitive humans. They befriend a girl who calls Bill 'Bie', Pete 'Pie', and Doc Tom 'Die Tie'. The girl has seen the ring before and they use her info to guess where it will be next. Their village is attacked by another tribe (not Neanderthals though) and they are in trouble but the ring arrives and they all leap through (including the girl). She is so frightened by the present world that she jumps back, but they figure that the drift of the ring would have carried her away from the hostile tribesmen.

I don't recall the 'must kill' incident, so this might not be the book, but the Rainbow Ring name of the time device rang a bell. It is a young adult book so it might be remembered as a short story.

  • I have a copy of Tunnel Through Time because I loved it when I was 12. There is no "must kill" in it, but Doc Tom has to shoot a native early human just before it would have killed them. It is a short book, easy reading for a kid. The ring when activated looks like a circular rainbow, which the young girl in the tribe notices. They have to make successive hops through time, instead of coming back all in one jump, when it is damaged by a brontosaur" bumbling into it. Commented Jun 5, 2019 at 0:51

Probably also a long shot, but Riley's Journey (by P.L. Parker, 2007) could fit the description. At least for the Ice Age time travel and Neanderthals part. I am not sure about the Rainbow device though.


Is this one of the stories of "The Company" by Kage Baker? Maybe in the short story collection "Black Projects, White Nights"

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    You should either comment if you don't know and guessing, or if you're answering, explain how the works march the question Commented Jul 1, 2015 at 22:24

Neither are short stories, but both Chad Oliver's "Mists of Dawn" published in 1952 and Victor Kelleher's "Fire Dancer" from 1996 have time travel and interaction with Neanderthals.

No time travel, but Lester Del Rey's "The Day is Done" is about the last Neanderthal trying to live with Cro-Magnons, but they end up killing him, I think.


The short story "Scout's Honor" by Terry Bisson is about time-travel and a modern day man interacting with Neanderthals. You can read it here:


It was originally published in "The Year's Best Science Fiction: Twenty-Second Annual Collection" which is available on Amazon:



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