"Beyond the Black River" takes place beyond the northern borders of Aquilonia, among settlers who dare to build homes for themselves in Pictish lands, a move Conan deems both unwise and, ultimately, untenable.
"... you Hyborians have expanded as far as you'll be allowed to expand. You've crossed the marches, burned a few villages, exterminated a few clans and pushed back the frontier to Black River; but I doubt if you'll even be able to hold what you've conquered, and you'll never push the frontier any further westward. Your idiotic king doesn't understand conditions here. He won't send you enough reinforcements, and there are not enough settlers to withstand the shock of a concerted attack from across the river."Balthus, a borderer and Conan's interlocutor in this dialog, cannot bring himself to believe this claim -- until he's reminded of the way the Cimmerians destroyed Venarium, a "red disaster" in which Conan himself participated as a youth: "I was one of the horde that swarmed over the walls. I hadn't yet seen fifteen snows, but already my name was repeated about the council fires." (Strangely, he makes no mention of his family being slain by Thulsa Doom or having become a slave lashed the Wheel of Pain -- an oversight on Howard's part, no doubt)
Conan accompanies Balthus back to Fort Tuscelan, where the Aquilonians have established themselves.
There, at the fort, civilization ended. This was no empty phrase. Fort Tuscelan was the last outpost of a civilized world; it represented the westernmost thrust of the dominant Hyborian races. Beyond the river the primitive still reigned in shadowy forests, brush-thatched huts where hung the grinning skulls of men, and mud-walled enclosures where fires flickered and drums rumbled, and spears were whetted in the hands of dark, silent men with tangled black hair and the eyes of serpents.Worse still, those "dark, silent men" have turned to a man named Zogar Sag to lead them. A wild sorcerer who spent time as a prisoner of the Aquilonians, Conan explains that "there'll be no peace on the border so long as Zogar lives and remembers the cell he sweated in." The governor of the fort thus begs Conan to slay Zogar before his designs against the Aquilonian settlements can come to fruition, a mission the Cimmerian accepts, taking with him a dozen men of his own choosing, none of them soldiers but all of them skilled foresters.
The remainder of the story describes Conan's efforts in the wilderness to find Zogar Sag before it is too late to save the Aquilonians. For the benefit of those who've never read the story before, I won't so any more about how events unfold, except that I find it hard to imagine how anyone, after reading this tale, could continue to suggest that Howard lacked either subtlety or insight. "Beyond the Black River" can't, I think, be read as an unapologetic paean to barbarism, as it is often portrayed. Like a lot of Westerns, which clearly served as its inspiration, the story regretfully suggests that civilized men are never a match for barbarians, which is why, being a barbarian himself, Conan knows how this latest clash between civilization and barbarism will end. It's one of my favorite Howard stories and well the time spent reading it.