What the achievement asks
The 4 main storylines of the Ohn'ahran Plains. Ten points, account-wide, both factions.
This is the levelling campaign of the zone, the one about the centaur clans and the Maruuk.
The 4 chapters, and the quest that opens each
| Chapter | Starts with | Ends with |
|---|---|---|
| Into the Plains | Next Steppes | Maruukai |
| Maruukai | Clan Teerai | The Nokhud Threat |
| Ohn'ahra's Blessing | Hooves of War | A Storm of Ill Tidings |
| Bonds Renewed | Chasing the Wind | Renewal of Vows |
The chapters run in order and each hands you the next, so in practice you only ever need the first quest name: Next Steppes. The rest is knowing where you stopped if you left halfway.
You very likely already have it
These are not side content. They are the quests the game gives you as you level from 60 to 70. Anyone who levelled through the Dragon Isles at the time finished this without noticing.
The exception is a character who skipped the campaign: a boost, a levelling event, or Chromie Time elsewhere. Those characters arrive at 70 having never set foot in the zone, and this is the achievement that tells them so.
It is account-wide, so one character doing it once settles it for good.
Do the optional ones on the same trip
Sojourner of Ohn'ahran Plains wants the optional storylines of the same zone, and those are the ones people genuinely miss. Both halves are needed for Loremaster of the Dragon Isles, so clear the zone once rather than coming back.
Where it fits
Part of Loremaster of the Dragon Isles, itself a piece of A World Awoken.