The Cipher of Damnation quest chain

The Earthen Ring has sent representatives to the horde and alliance, seeking help communing with the spirits of Shadowmoon Valley, and healing the damage done to the valley. In the process, you discover how the land was shattered, and defeat an elemental lord.

This quest has several dialogs and a couple of cut scenes that explain details not found otherwise.

The Hand of Gul'dan

 * The Hand of Gul'dan (quest)
 * Enraged Spirits of Fire and Earth
 * Enraged Spirits of Water
 * Enraged Spirits of Air

Oronok Torn-heart

 * Oronok Torn-heart (quest)
 * I Was A Lot Of Things...
 * A Lesson Learned
 * The Cipher of Damnation - Truth and History

Finding the first fragment

 * Grom'tor, Son of Oronok (quest)
 * The Cipher of Damnation - Grom'tor's Charge
 * The Cipher of Damnation - The First Fragment Recovered

Seeking the second fragment

 * Ar'tor, Son of Oronok (quest)
 * Demonic Crystal Prisons
 * Lohn'goron, Bow of the Torn-heart
 * The Cipher of Damnation - Ar'tor's Charge
 * The Cipher of Damnation - The Second Fragment Recovered

The trail of the third fragment

 * Borak, Son of Oronok (quest)
 * Of Thistleheads and Eggs...
 * The Bundle of Bloodthistle
 * To Catch A Thistlehead
 * The Shadowmoon Shuffle
 * What Illidan Wants, Illidan Gets...
 * The Cipher of Damnation - Borak's Charge
 * The Cipher of Damnation - The Third Fragment Recovered

Defeating the fire lord

 * The Cipher of Damnation (quest)

Rewards
Also, one of the following:
 * Amulet of the Torn-Heart

As well, several lesser items from the individual quests, including some tubers from Oronok's farm.