As written above you need to gather a shiny to start the quest. However, the shiny will not be visible unless you wear Toggery's Tinkered Excavation Cap, the reward from the quest Tinkering with Toggery. You can see the shiny with the D.I.R.T.Y. Excavation Helmet too.
The shiny is directly to the right of the zone line; you can zone in, get the shiny and zone out without engaging any mobs at all.
Steps
Find a way to identify this mysterious thread
Talk to Frederick Saltmarsh on the Lavastorm docks ( -166, -120, 653 ) Copy/waypoint -166, -120, 653. Depending on what chat option you choose he wants 1p or 50g to identify the thread.
Listen to what Frederick has to say
He will give back your coin when he finds out what the thread is. He won't tell you what he actually found out, though, except that he won't stand in the way of Najena.
Seek out someone INSANE! to help identify the mysterious thread
Find Toggery von Gearbender inside Temple of Solusek Ro ( -246, -60, -657 ) Copy/waypoint -246, -60, -657 and ask him a question or two
Investigate the The Deep Forge for clues about the robes the gnome spoke of
Talk to Ruddybupp, found at the Netherflame Forge ( 88, 1, 4 ) Copy/waypoint 88, 1, 4
Ruddybupp wants a full set of Magmatic Bronze Armor in return for a special robe. This armour can be crafted from recipes that drop from any mob in the zone (Chest Drops).
Obtain a Magmatic Bronze Chestplate
Obtain a pair of Magmatic Bronze Legplates
Obtain a Magmatic Bronze Helm
Obtain a pair of Magmatic Bronze Spaulders
Obtain a pair of Magmatic Bronze Bracers
Obtain a pair of Magmatic Bronze Boots
Obtain a pair of Magmatic Bronze Gauntlets
Ruddybupp wants you to get him a book from Najena's Hollow called "Bows and Ammo: volume 14". This can be found outside the jail cells on a shelf at ( -20, -195, -139 ) Copy/waypoint -19.98, -194.86, -138.72.
Return to Ruddybupp with the book.
Ruddybupp sets up a meeting for you with Lady Najena at the Magma Grotto in Lavastorm ( -250, -129, 481 ) Copy/waypoint -249.69, -129.11, 480.95. When you speak with her she agrees to give you a magical robe if you can pass her trial to prove you are worthy of one.
A discussion page exists which may contain more information