Nyarlathotep, the Other God, incarnate as a golden boy-Pharoah, speaks to Randolph Carter almost as if they were equals.  It — he — exposits the following.

1) Carter’s quest has destroyed those before him who attempted it — Barzai, whom you remember from way back in Ulthar, and somebody named Zenig whose skull is now set in a ring on Nyarlathotep’s little finger.

2) The Great Ones have abandoned their own onyx castle in favor of Carter’s dreamed-up sunset city.  They no longer do whatever the gods of the Dreamland are supposed to do, and merely walk the streets and plazas of Carter’s city.

3) Nyarlathotep therefore spares Carter’s life and orders him to travel to the sunset city and evict the gods, that they will return to their own thrones.  By [Carter] alone… may [the gods] be sent back to their world.  In that half-waking dreamland which is [the sunset-city], no power of uttermost night may pursue.

4) Surprise twist!  The sunset-city, which the two bearded priests and the old priest in Ulthar and the leader of the cats of Celephais and King Kuranes and probably other experts besides whom I have forgotten, which all of those people declared to probably be a dreamworld reflection of Carter’s boyhood homes and experiences, is a dreamworld reflection of Carter’s own boyhood home and experiences.

5) It is the glory of Boston’s hillside roofs and western windows aflame with sunset, of the flower-fragrant Common and the great dome on the hill and the tangle of gables and chimneys in the violet valley where the many-bridged Charles flows drowsily… There is Providence quaint and lordly on its seven hills over the blue harbour, with terraces of green leading up to steeples and citadels of living antiquity, and Newport climbing wraithlike from its dreaming breakwater. Arkham is there, with its moss-grown gambrel roofs and the rocky rolling meadows behind it; and antediluvian Kingsport hoary with stacked chimneys and deserted quays and overhanging gables, and the marvel of high cliffs and the milky-misted ocean with tolling buoys beyond.

6) All Carter needs to do is go there, and find the Great Ones, and remind them of their childhood homes, and they’ll be overcome with nostalgia, and boom, they go back to doing their godly duties and Carter can have his city.

7) Nyarlathotep will send Carter there.  Also, he’s totally Nyarlathotep.

So that’s a lot to take in, and before Carter has fully processed it, he finds himself on the back of a Shantak riding through interstellar space.  But!  The Shantak isn’t taking him to the sunset-city!  The Shantak is taking him to the mindless daemon-sultan Azathoth, which  bubbles and blasphemes at infinity’s centre!

Why?

Because Nyarlathotep is a jerk, that’s why!

Carter’s life flashes before his eyes!  He’s come so far, gotten so close, and now he’s about to be eaten by an infinitely large monster!  This is it!  The end!

Carter reflects on Boston, his home, which Nyarlathotep had so recently extolled, and then he has an idea.

Carter wakes up.

Out of the void S’ngac the violet gas had pointed the way, and archaic Nodens was bellowing his guidance from unhinted deeps… Stars swelled to dawns, and dawns burst into fountains of gold, carmine, and purple, and still the dreamer fell. Cries rent the aether as ribbons of light beat back the fiends from outside. And hoary Nodens raised a howl of triumph when Nyarlathotep, close on his quarry, stopped baffled by a glare that seared his formless hunting-horrors to grey dust. Randolph Carter had indeed descended at last the wide marmoreal flights to his marvellous city, for he was come again to the fair New England world that had wrought him.

So to the organ chords of morning’s myriad whistles, and dawn’s blaze thrown dazzling through purple panes by the great gold dome of the State House on the hill, Randolph Carter leaped shoutingly awake within his Boston room.

And that’s the Dream-Quest of Unknown Kadath!  We fade to black, roll the closing credits.  There’s a post-credits teaser of Nyarlathotep [striding] brooding into the onyx castle atop unknown Kadath in the cold waste, and [taunting] insolently the mild gods of earth whom he had snatched abruptly from their scented revels in the marvellous sunset city but that’s it.

The end!  No moral.