“Seeking Disclosure” is the umbrella quest that ties the middle of the Dawnguard story together: bring the two missing Elder Scrolls to the Moth Priest Dexion Evicus. It runs in the background while you do Scroll Scouting, Chasing Echoes and Beyond Death.
How it starts
It begins after “Prophet”, whichever side you’re on.
Walkthrough
Elder Scroll (Dragon)
If you kept the scroll from Elder Knowledge, you already have it. If you sold it to Urag gro-Shub, or never had it, Scroll Scouting handles the search.
Elder Scroll (Blood)
This one belongs to Valerica, and you’ll get it at the end of Beyond Death in the Soul Cairn.
Delivering the scrolls
Take both to Dexion: at Fort Dawnguard if you’re with Isran, at Castle Volkihar if you serve Harkon. There’s a problem. Reading an Elder Scroll without proper preparation has cost Dexion his sight, and he can’t read any more of them.
He tells you the Blood scroll is the key to the prophecy, hands you the third scroll and explains the old Moth Priest method: the Ritual of the Ancestor Moth at the Ancestor Glade in the pine forest of southern Skyrim. That’s the next quest, Unseen Visions.
Notes
The two sides only differ in where Dexion is and how the journal is worded – there are no choices here. Sources disagree slightly on exactly which reading blinded Dexion, but the result is the same: from now on, you do the reading yourself.