Preserve the True Future

You have 15 minutes until Chromie die, so investigate shrines across Draginblight. If cant realise what to do:

• Azure dragonblight - slay elementals and loot [item=151141]. When got 50, combine them to [item=150941].
  You'll get Voidcallers' Scroll quest, fly to floating disc, turn it in and defeat [npc=122553]. Loot [item=150943] to open portal to Hyjal.
• 
  
• Ruby dragonblight - slay three elites in the shrine, loot three [item=150939] and combine to [item=150940].
  You'll get Soul Crystal quest, fly to the cave in a tree, turn it in and defeat [npc=122874]. Loot [item=150946] to open portal to The Culling of Stratholme.
• 
  
• Emerald dragonblight - slay mobs to collect 10 [item=151167] and 8 [item=151168] and combine to [item=151166]. Use it and slay two mobs that channeling to a tree protector. There are three protectors in the shrine, so you have to to that three times. After that you'll get The Ancients' Wisdom. Turn it in near the water next to a bone hand, slay [npc=122875] and loot [item=150945] to open the portal to Andoral.
• 
  
• Obsidian dragonblight - get through the cave and defeat [npc=122528]. Loot [item=150938] and get out of the cave. Turin in Demonic Corestone when leaved and slay [npc=122871].
  Loot Fel-Touched Chronoshard to be able to open the portal to Well of Eternity.
• 
  

Azure dragonblight - https://www.youtube.com/watch?v=c897rfTPSOs
Ruby dragonblight - https://www.youtube.com/watch?v=PN8sR5TP6Us
Emerald dragonblight - https://www.youtube.com/watch?v=xe8bMwta31Y
Obsidian dragonblight - https://www.youtube.com/watch?v=Rgyd9FhXuvA

The Deaths of Chromine quest chain consist of few parts, I hide some data under the spoiler:

Spoiler

The quest chain:

1. 
   
2. The Day That Chromie Dies - just see that she dies.
3. 
   
4. Rewind - the same one, but you'll have to speak with dragons before Chromie dies.
5. 
   
6. The Many Advantages of Being a Time Dragon - you'll have 15 minutes to get some info about attackers. Chromie dies when the time ends.
7. 
   
8. Preserve the True Future - there are four shrines across Dragonblight, you have 15 minutes to stop the attacks.
   During the quest you get info that there are also four other attacks you have to stop
9. 
   
10. The Deaths of Chromie - now you have to stop all eight attacks in one attempt.

If you cant realise what to do in dragonshrines, there are small guides:

• Azure dragonblight - slay elementals and loot [item=151141]. When got 50, combine them to [item=150941].
  You'll get Voidcallers' Scroll quest, fly to floating disc, turn it in and defeat [npc=122553]. Loot [item=150943] to open portal to Hyjal.
• 
  
• Ruby dragonblight - slay three elites in the shrine, loot three [item=150939] and combine to [item=150940].
  You'll get Soul Crystal quest, fly to the cave in a tree, turn it in and defeat [npc=122874]. Loot [item=150946] to open portal to The Culling of Stratholme.
• 
  
• Emerald dragonblight - slay mobs to collect 10 [item=151167] and 8 [item=151168] and combine to [item=151166]. Use it and slay two mobs that channeling to a tree protector. There are three protectors in the shrine, so you have to to that three times. After that you'll get The Ancients' Wisdom. Turn it in near the water next to a bone hand, slay [npc=122875] and loot [item=150945] to open the portal to Andoral.
• 
  
• Obsidian dragonblight - get through the cave and defeat [npc=122528]. Loot [item=150938] and get out of the cave. Turin in Demonic Corestone when leaved and slay [npc=122871].
  Loot Fel-Touched Chronoshard to be able to open the portal to Well of Eternity.
• 
  

Azure dragonblight - https://www.youtube.com/watch?v=c897rfTPSOs
Ruby dragonblight - https://www.youtube.com/watch?v=PN8sR5TP6Us
Emerald dragonblight - https://www.youtube.com/watch?v=xe8bMwta31Y
Obsidian dragonblight - https://www.youtube.com/watch?v=Rgyd9FhXuvA

Great, now some info about instance scenarios:

• 
  
• The Well of Eternity just run it from the end to the entrance and slay [npc=123721]
• 
  
• Mount Hyjal - get close to Chromie's body and slay few waves of mobs.
• 
  
• Battle for Andoral - during Sky Ablaze With Cannonfire quest you have to defeat enormous gun. It has 80% damage reduction and the same chance to avoid damage.
  There are few elites (such as [npc=124101]) that drops items to disable those buffs. There are also war-captains which drop [item=151370]. Use that to destroy the cannon faster.
• 
  
• The culling of Stratholme - you have to finish quests: Smoke, Meat, and Pretty Flowers, Yeah, Definitely for the Kids, [quest=47746],
  [quest=47750] and [quest=47747]. As you done run through the scenario as you run through the instance in CoT. Slay [npc=123836] in the end.
• 
  

The Well of Eternity - https://www.youtube.com/watch?v=-FxGEebrFc4
Mount Hyjal - https://www.youtube.com/watch?v=lliqQKEKsak
Battle for Andoral - https://www.youtube.com/watch?v=4Y8vuJpfwh4
The culling of Stratholme - https://www.youtube.com/watch?v=vcdf3QhRvHc

Rewards:

• 
  
• [item=151692]
• 
  
• [item=151693]
• 
  
• [item=151694]
• 
  
• [item=151695]
• 
  

Ok.. here's the parts that I think most people are missing: first, your IL is raised to 1000 and your lvl to 112, so damage isn't the issue nor is gear. Second, you can do the shrines in you own time. You have 15 minutes for each. Once you complete them all, start a new instance and you only have to kill the bosses. Third, the Chrono-portal bosses are NOT required for the base questline, only the bonus. GL with that until Chromie is maxed.

There are a lot of mechanics happening in this scenario; it will take time for you to complete it and it will not be done in one try.

What to do (early stages):

1. 
   
2. Fly to one of the four areas around Wyrmrest that need your attention.
3. 
   
4. Kill whatever mobs you find there, gain rep and collect the items they drop.
5. 
   
6. Use the items to summon a boss for that area; kill and loot the boss.
7. 
   
8. Finish the quest with Chromie to open a portal up in the Temple.
9. 
   

Chromie will get killed when the time runs out. Choose a different area for your next attempt until all bosses are summoned.

What to do (later stages):

Your ultimate goal is to kill all bosses in one run, within 15 minutes.

You will not be able to do this at first, but as you raise your rep and run the fights a few times several mechanics change which help.

• 
  
• Rep with Chromie makes things much easier / faster; take every chance to earn rep that you can.
• 
  
• Your gear is irrelevant: your player level goes to 112 and item level is fixed at 1000 for the scenario.
• 
  
• Experiment with your spec - the mechanics change. For example, as druid I preferred heal spec to boomkin. YMMV.
• 
  
• Dragonshrine bosses will spawn immediately once you've summoned them the first time.
• 
  
• In early stages choose rep from [item=151493]; when making your final run take buffs and speed items.
• 
  
• If [item=151554] is offered from Sands of Time, it may drop helpful speed-up items.
• 
  
• Extra [item=151493] can be found by killing a silver-portrait mob outside the entrance of each Dragonshrine.
• 
  
  

Good luck!
[EDIT] This guide is long but very helpful: [guide=5193]