The point here is, in general, there's no time to explain, but the fact is a fact! No matter how, possibly with the help of a time machine, it is not known, but our hero is back to the past, far-distant past, and now he's in trouble! So now he's got a fireplace century, a bunch of Neanderthals aggressive, and he alone, and they attacked him. Well, he had not even build a large fortress and strength he has many, though can fend stones. Join him and help him stop the rabid crowd of savages, so they did not destroy the barrier and did not kill our hero. Good luck!