The Mariner will tell about a mysterious creature that has been destroying boats leaving and coming into Far Harbor.
She will then ask to go to the boat and she will go to hers. Before boarding on, the player character is stopped by Avery, who tells it is an old myth and the player character is wasting time and putting themselves in danger.
The Sole Survivor will then board on the boat which has already been programmed by the Mariner to go to Red Death Island.
Once arriving, the player character has to look for the Red Death.
Talk with the Mariner about finding Red Death. It will then appear, revealing itself to be a tiny bloodrage mirelurk.
Vanquish the Red Death.
The Mariner will be very disappointed, but will still reward the Sole Survivor with the Legend of the Harbor, a unique version of the Fisherman's outfit. She will ask if the Sole Survivor wants to tell the truth about the monster or lie. One will then get back onto the boat and sail back to Far Harbor.
The player character will then receive a hero's welcome from the town's people depending on if choosing to lie or not. If the player tells the Mariner to tell the truth, the townspeople will jeer and mock the Mariner. If the player chooses to embellish the tale, the townsfolk will be in awe of her.
If you have the evidence from DiMA's secret medical facility, but have not yet confronted DiMA or Captain Avery for the quest The Way Life Should Be, Avery will have that dialogue instead of the lines for this quest. As a result, Avery and the Mariner will simply stand beside your boat, with Avery initiating dialogue each time you approach her. To continue the quest, simply climb aboard your boat and head for Red Death Island.
If you kill Machete Mike during the Hull Breach quest unprovoked, then you will be locked out of this quest as the completion of this quest-line is a prerequisite.
pcps4xboxone Completing the main DLC questline may cause this quest to become unavailable. [verified]
The only known fix is to reload a save from before completing the main questline.
pcps4xboxone When travelling to Red Death Island it's possible getting a black screen but still being able to move, but landing in water. To fix this one must activate the Vault-Tec Assisted Targeting System (travel to the destination and target the Red Death in V.A.T.S., or hold down the V.A.T.S. activation button). [verified]
pcps4xboxone Possibly related to the above glitch, the player's boat may disappear, but the prompt to activate the boat's controls will still appear just off the northeastern coast of Red Death Island. The boat will be entirely invisible. Objects can still collide with the boat and the player is forbidden from fast traveling after activating the controls to return to the docks of Far Harbor. Use your best pixelhunting skills to activate the quest marker which will trigger the returning sequence. After a few seconds the screen will fade to black and you'll find yourself on a boat returning to Far Harbor. [verified]
pcps4xboxone After the boat pulls away from the dock and the game starts a loading screen, the one may be dropped in the ocean without the boat near the target island. Opening the console and typing movetoqt xx02399f will move the player character to the correct location, but the boat will still not be present. To return to Far Harbor, the quest marker points to an activator floating in mid-air where the boat should be. Activate it and wait a moment and the player character will load on the boat as it arrives back in Far Harbor. [verified]