At Stonecrest town, find the Sheriff Grant Hornkeep. Say Secret Documents and he will ask you to bring him 5 of them.

Go to the following places:

First open the chest at Mayor Fairweather's residence. You will find a Shiny Metal Key.

Then open the Shiny Metal chest at Gulfrid's Weapon Shop and you should find a Dark Iron Key.

Now open the Dark Iron chest at Herewald's Armor Shop and you should find a Chipped Bone Key.

And now open the Chipped Bone chest at Mithanna Snowraven's house and you should find a Steel Safe Key.

Finally go to Thieve's Hideaway and open the Steel Safe. You should find a Secret Document.

Collect 5 Secret Documents and go to Sheriff Grant Hornkeep. Keyword: Secret Document, Yes and yo u will be rewarded with a Certificate of Recognition and 2.500 experience point * your current level and 3.500 gold pieces * your current level.

Collect 6 Certificates of Recognition and go to Mayor Fairweather. Keyword: Certificate of Recognition and you will be rewarded with a Lost Helm of the Dragon and 2.000 experience points * your current level and 1.000 gold pieces * your current level.

Note 1: Every time you open a chest, your key crumples to dust. The chests will not always drop the keys, they may drop something else. If this happened you must start all over cause you don't have the previous keys anymore. If someone else has opened the chests recently, it will take some time (about 30 min) to spawn again.

Note 2: You can do this quest as many times as you want.

Quest Reward Synopsis: Lost Helm of the Dragon (150 End, 30 Int, 46 Wis), 17.000 experience points * your current level, 22.000 gold pieces * current level.