The demo reads 111 words in 45.1 seconds, close to 2.5 words a second, in a cinematic look: a cloaked figure in a torchlit corridor, a crown on red velvet, a young girl with her hand on a dragon, a frozen river under stone towers, and three heraldic banners. The script never names a character. It speaks of “a girl who wakes a dragon” and “a throne that invites treachery”, which keeps it free of spoilers for every season.
That choice cuts both ways. Newcomers can watch safely, but longtime fans hear nothing they did not already know. For a lore channel, one named moment beats a general mood: Aegon landing on the hill where King's Landing would be built, or Ned Stark agreeing to ride south as Hand of the King.
Two details are worth copying. The final scene shows a banner with readable writing, “Comment below to decide the fate”, so the call to action appears on screen as well as in the voice. And the last spoken line, “Tell me which house you'd pledge, and why”, is the kind of question this fandom answers at length.
If you reuse the format, cut one ornamental phrase, such as “a quiet, inexorable flame”, and spend those seconds on a fact.