Skyrim: Beyond Death
Beyond Death is a main story quest in Skyrim: Dawnguard.
 Starting Location
Serana and I have entered the Soul Cairn in pursuit of her estranged mother, Valerica, and the Elder Scroll she took when she fled Castle Volkihar.
Kill the Boneyard Keepers
Retrieve the Elder Scroll (Blood)
Find Valerica behind some sort of energy barrier.
Kill all Boneyard Keepers to bring the barrier down. They are in different locations around the Soul Cairn, just follow the markers on the map. Use Arvak's Mount to travel faster.
Kill the Dragon, Durnehviir, that attacks
Get the Elder Scroll