This quest is essentially a run through the Black Cove. The quest is obtained when you come across a dying orc just down the start of the Black Cove.
(Getting to the Black Cove) Head through the Western gate directly West of the Cyseal Harbour Waypoint Portal. Head North past the dead orcs, then West past the crying orc from The Grieving Orc quest and North past the minefield of traps.
There is an orc miniboss called Grullbarg the Fearsome guarding the entrance to the Black Cove. Kill him and enter the Cove (6750 Battle XP).
Head East into the dungeon past the dying orc. There is a fight between Orcs and Skeletons here. Join the fight if you want the extra XP (10695 XP) or you can kill the survivors. You could also completely ignore them for now as we will be back here later.
Continue East, disabling the Poison Cloud traps and take out the Source Abomination mini boss. Since you're here, enter the room East of the Abomination to obtain and quickly solve the Another Crazed Mage quest.
In the room North of the Abomination, pull the lever and then the switch behind the painting. This will reveal a trapdoor that we'll come back to after exploring and grabbing the quest Headless Nick at the end of the path to the North.
Enter the trapdoor and head East, navigating the crabs and traps as you go along. The key to the locked, unbreakable chest before the first bridge here can be found behind some rocks by a shipwreck to the Northwest. Continue East until you get to the room full of switches.
Source Abomination
(Optional) For some extra loot, trigger the 'Ominous Switch' along the Western wall. You may need a few points in perception to see the switch. A chest is hidden in the foliage. Use your teleporter pyramid to regroup.
Back to the room of switches, go south east down some stairs and you will find a hidden 'Blood-Stained Switch' West of the stairs behind some bushes. Press the switch to open up the locked doorway (840 XP).
Head through the newly opened door and face and kill Pontius for 5550 XP and +1 Reputation. This completes the quest.
Grab his key and open his chest on the ship for a Blood Stone.
Use the stone if you want to unlock another room in your Homestead or save it as you'll need one for the upcoming An-A-Mount Of Healing Magic quest.
You will also want to head to the scene of the fight between the Orcs and Skeletons to open a locked door with your newly acquired key. This route contains a miniboss that you need to get by to progress Kitty Love and Lost Love at the Lighthouse.
