Can't Start Quest - The Hand of Fate

Before you can start The Hand of Fate (Alliance/Horde), your character must be at least level 45, have completed a quest to obtain an Artifact weapon, and your account must have completed the following quests on the character you would like to start the quest on.

• Uniting the Isles - If you have completed this on another character, you will be able to pick it up and immediately complete it with Khadgar in the Violet Citadel
• Armies of Legionfall - If you have completed this on another character, you can pick this up from Khadgar in Krasus' landing after completing Uniting the Isles and complete it immediately.
• Assault on Broken Shore - If you have completed this on another character, you can pick this up from Khadgar in Krasus' Landing, choose the option to skip the scenario, and complete it in the Broken Shore.

Once you have completed these steps, go back to Dalaran and visit Khadgar in the Violet Citadel to pick up The Hand of Fate.

If this doesn't fix the issue for you, your character may need to work around the issue by speaking to Lady Liadrin (for Horde charcters) or Vereesa Windrunner (for Alliance characters), which should allow you to start the quest chain for Argus.

Note: If you completed quests on another character and this character has not been offered the quests, you may need to log out of this character, log in to the character who initially completed the quests, and then log back in on the character you're having problems with. Once you log back in, the quest should be available.