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Horror from the Deep

Written by Dev on . Posted in OSRS Quests

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Horror from the Deep OSRS Quest Guide

Mend the lighthouse beacon, uncover the mystery beneath it, and overcome the colour-shifting Dagannoth Mother.

Quest Overview

Start location
Speak with Larrissa by the lighthouse, north of the Barbarian Outpost.
Difficulty
Intermediate
Estimated length
Medium
Synopsis
The lighthouse beacon has ceased functioning and its keeper has vanished. Help fix the light, investigate the strange events below, and defeat the creature responsible.
Requirements
Completion of Alfred Grimhand's Barcrawl. You must also be capable of defeating Dagannoth enemies.
Items needed
60 steel nails, 2 planks, hammer, molten glass, swamp tar, tinderbox, sword, arrow, air rune, water rune, earth rune and fire rune.
Recommended
Food, prayer potions, teleport, melee weapon, ranged weapon, and runes or staves for air, water, earth and fire spells.
Enemy
Dagannoth Mother.

Quick Info

Difficulty: Intermediate

Length: Medium

Start: Larrissa by the lighthouse exterior.

Required miniquest: Alfred Grimhand's Barcrawl.

Main danger: Colour-shifting Dagannoth Mother.

Useful travel: Games necklace to the Barbarian Outpost.

Required Items

  • 60 steel nails
  • 2 regular planks
  • Hammer
  • Molten glass
  • Swamp tar
  • Tinderbox
  • 1 sword
  • 1 arrow
  • 1 air rune
  • 1 water rune
  • 1 earth rune
  • 1 fire rune

Walkthrough

  1. Converse with Larrissa outside the lighthouse and agree to assist her.

  1. Journey to the Barbarian Outpost and speak to Gunnjorn to get the lighthouse key.
  2. Return to the lighthouse and fix the bridge using your planks, steel nails and hammer.
  3. Enter the lighthouse and climb up to the top floor.
  4. Repair the lighthouse light using swamp tar, molten glass and a tinderbox.
  5. Go back to Larrissa, then re-enter the lighthouse and search the bookcase for clues.
  6. Head down into the lower section of the lighthouse and keep going until you find the strange wall.
  7. Use the sword, arrow, air rune, water rune, earth rune and fire rune on the wall to unlock the path ahead.
  8. Speak to Jossik in the cavern below the lighthouse.
  9. Defeat the first Dagannoth that attacks you.

 

  1. Get ready for the Dagannoth Mother fight right after.

Dagannoth Mother Fight

Important: The Dagannoth Mother shifts colour during the fight. Each colour must be struck with the correct combat style.

 

White: Attack using air spells.
Blue: Attack using water spells.
Brown: Attack using earth spells.
Red: Attack using fire spells.
Green: Attack using Ranged.
Orange: Attack using Melee.

Completing the Quest

  1. After defeating the Dagannoth Mother, collect the rusty casket.
  2. Speak to Jossik again.
  3. Choose a damaged god book to complete the quest.

Rewards

  • 2 Quest Points
  • 4,662.5 Magic experience
  • 4,662.5 Strength experience
  • 4,662.5 Ranged experience
  • A damaged god book of your choice
  • Access to the lighthouse Dagannoth area
  • Access to Jossik's god book shop

God Book Choice

At the end of the quest, you can choose a damaged god book. The book is not complete until you add the correct pages to it.

Holy book: Saradomin.
Unholy book: Zamorak.
Book of balance: Guthix.

Tips

  • Bring all required items before travelling to the lighthouse.
  • Keep your melee, ranged and magic options easy to click during the boss fight.
  • Use Protect from Missiles or Protect from Melee if needed.
  • Do not try to kill the Dagannoth Mother with one combat style only.
  • Bring a teleport so you can leave quickly after finishing.