This quest begins when a mysterious man knocks you off from the Abyss to Pywel - which takes place at the end of the "Obsession and Madness" quest.
With Octavius gone and a new shadow looming, the dean must be alerted, and a strategy devised, to face this emerging danger. Seek out the dean.
Reward: Honey Tea x10
You talk to Dean Grundir automatically, during the cutscene.
Return to your camp in any way you choose - the fastest way, of course, will be to teleport to a nearby Abyss Nexus - and enter the tent. This will complete both this quest and the entire fourth chapter of the game.
News of the Abyss encounter left Grundir in a state of solemn reflection. Weighing Octavius' message against the strange being discovered in the depths, he became convinced that the rift-maker is the catalyst for this entire catastrophe. For now, put aside these complex matters and return to Howling Hill.