HI, are you referring to the main storyline to get to Zaralek Caverns that was added in patch 10.1.0?
If so, you can find it in Leveling ⟫ Dragonflight ⟫ Embers of Neltharion (70+ Storyline)
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If you are not paying for a subscription and you can’t see this in the above location, then you may need to check out your Members ⟫ Products and see if there’s Dragonflight Achievements or Dragonflight Update. However, if you have Loyalty unlocked before it was removed and you still don’t have this guide, you can submit a ticket and Dragonflight Achievements can be manually applied. This is only if you have earned the loyalty status before it was removed, not after.
I hope this helps 👍😉