This quest is not available in game.
Bring a Libram of Rapidity, 1 Pristine Black Diamond, 2 Large Brilliant Shards, and 2 Blood of Heroes to Lorekeeper Lydros in Dire Maul to receive an Arcanum of Rapidity.
Master Winthalus lost the Libram of Rapidity in the east wing. The Libram will allow for a minor haste cantrip to be placed upon your equipment. Parlor tricks, really...
Regardless, if you are interested, you will need to present the Libram along with some basic reagents.
Hrm... I believe it also requires blood of heroes, a pristine black diamond, and large brilliant shards. I could be wrong!