Find the Path to the Underdark

Key takeaways

Use the route that best matches the areas you have already explored, but prepare for a transition into a more dangerous region.

• You only need one entrance The quest is completed as a route-finding objective once you successfully reach the Underdark. The four entrances are alternatives, not four mandatory objectives.
• Each route has a different obstacle The Defiled Temple, Whispering Depths, Zhentarim Hideout, and Overgrown Tunnel do not present the same encounter or access method. Inspect the area around the entrance before committing to a descent.
• Prepare before descending The Underdark is a major Act 1 region rather than a short shortcut. Heal, restore useful abilities, and resolve urgent nearby situations before taking an entrance that may move the party away from the surface.
• The Mountain Pass is separate Reaching the Underdark is essential for parties continuing the main story without using the Mountain Pass. It is not necessary to visit every possible route to satisfy that progression.

Find the Path to the Underdark overview

Find the Path to the Underdark is an Act 1 objective that directs the party toward one of the major routes beneath the surface.

Finding the path to the Underdark is a critical Act 1 objective for parties seeking to continue toward Moonrise Towers. The quest is less a single linear dungeon crawl than a destination problem: the overworld contains four distinct entrances, and each entrance leads through a different local situation before the party can descend. Your choice of route can therefore determine which enemies, NPCs, and nearby quests you encounter first.

The four known approaches are the Defiled Temple, the Whispering Depths, the Zhentarim Hideout, and the Overgrown Tunnel. They are scattered across the overworld and are guarded or concealed in different ways. The Defiled Temple route requires dealing with True Soul Gut and obtaining a key, while the Whispering Depths route centers on a dangerous fall through a green-hued opening. The Zhentarim Hideout uses an illusory wall and a secret elevator, and the Overgrown Tunnel becomes available while pursuing Mayrina through the quest involving Auntie Ethel.

There is no requirement to clear every entrance before entering the Underdark. Once one route has been successfully navigated, the party can continue below the surface and begin exploring the Underdark itself. This destination is especially important for characters following Halsin and the refugees, and for main-story progression when the party is not using the Mountain Pass. After arriving, the Myconid colony offers opportunities to meet Blurg and Omeluum and to branch into further Underdark content.

Where this sits

Requirements and preparation

No single entrance is mandatory, but each route has its own access condition or danger.

• RequiredAccess to the Act 1 overworldThe party must be able to explore the surface regions where the four entrances are found.
• RequiredA plan for the chosen entranceCheck whether the route involves a hostile encounter, a key, a hidden passage, or a hazardous descent before entering.
• RecommendedFeather Fall or another safe descent methodThis is particularly important for the Whispering Depths route, where the entrance involves jumping through a green-hued hole.
• RecommendedHealing and party resourcesThe destination is dangerous and may contain encounters immediately after arrival. Rest and prepare before committing to the transition.
• OptionalProgress in the Auntie Ethel storylineThe Overgrown Tunnel path is discovered while pursuing Mayrina through the quest to save her from Auntie Ethel.

Objectives

1. Find an entrance to the UnderdarkSearch the overworld for one of the four known routes rather than treating every entrance as a required destination.
2. Overcome the entrance's guardian or obstacleThe selected route may involve hostile agents, a powerful creature, a key, a concealed passage, or a dangerous drop.
3. Enter the UnderdarkSuccessfully cross the route boundary and arrive below the surface to advance the objective.
4. Continue toward Moonrise TowersUse the Underdark as a major Act 1 route for parties that are not progressing through the Mountain Pass.
5. Meet the inhabitants of the UnderdarkAfter arrival, the Myconid colony can introduce the party to Blurg and Omeluum.Optional

Walkthrough

1. 01

   Find a route into the Underdark

   Choose which entrance to pursue

   Review the four known approaches before committing to one: the Defiled Temple, Whispering Depths, Zhentarim Hideout, and Overgrown Tunnel. You do not need to clear all four, so choose the route that fits the areas and storylines your party has already reached.

   TipKeep a backup route in mind if the first entrance is guarded by a fight your party is not ready to handle.

   Checkpoint
2. 02

   Secure the key and open the route

   Use the Defiled Temple route

   In the Defiled Temple, deal with True Soul Gut and obtain the key needed to access the way below. This path is not simply an unlocked door: failing to account for the temple's hostile presence can turn the approach into a direct confrontation.

   Location: Defiled Temple

   Watch outDo not assume the temple entrance is safe because the route is indoors; True Soul Gut and the surrounding agents are the defining obstacle.

3. 03

   Survive the descent into the Underdark

   Descend through the Whispering Depths

   The Whispering Depths route uses a green-hued hole as its descent point. Jumping without a way to reduce fall damage can kill or badly injure party members, so apply Feather Fall or use another reliable method of surviving the drop before committing to the jump.

   Location: Whispering Depths

   TipCast the descent-protection effect before the jump, not after the first character has already fallen.

   Watch outAn unprotected drop is the main failure risk on this route.

4. 04

   Locate and operate the secret elevator

   Find the hidden passage in the Zhentarim Hideout

   The Zhentarim Hideout contains a secret elevator route behind an illusory wall. Search the hideout carefully and interact with the concealed passage rather than expecting a clearly marked staircase to the Underdark.

   Location: Zhentarim Hideout

   TipIf the route is not obvious, inspect suspicious walls and use characters or abilities suited to revealing hidden interactions.

   Watch outThe hideout is associated with Zhentarim agents, so entering their area can create a social or combat problem before the elevator is available.

5. 05

   Reach the Underdark through the Mayrina storyline

   Follow the Overgrown Tunnel during Mayrina's rescue

   The Overgrown Tunnel path is discovered while progressing through the quest to save Mayrina from Auntie Ethel. Advance through that storyline and treat the tunnel as a route revealed by the rescue investigation rather than as an isolated surface entrance.

   Location: Overgrown Tunnel

   TipIf you are already pursuing Mayrina, this route can combine the Underdark objective with your existing investigation.

   Watch outThe tunnel is tied to an active character rescue situation; leaving that storyline unresolved may change what content you see around the route.

6. 06

   Reach the Underdark

   Cross into the Underdark

   After overcoming the selected entrance's obstacle, take the passage, elevator, or descent that leads below the surface. Confirm that the party has fully entered the Underdark before treating the objective as complete, then establish a safe position and prepare for regional exploration.

   Location: Underdark

   Checkpoint
7. 07

   Continue Act 1 progression

   Explore the Myconid colony

   Once inside, continue exploring until you can reach the Myconid colony and encounter notable characters such as Blurg and Omeluum. These encounters are part of the wider Underdark content rather than a requirement to use every entrance.

   Location: Myconid colony

   TipUse the first safe opportunity after arrival to orient yourself, because the Underdark is a full region with its own encounters and quests.

Mission mechanics

This objective uses branching access rather than a conventional sequence of combat arenas. The party can reach the same broad destination through four distinct overworld entrances, and the chosen entrance determines the immediate problem: a key associated with True Soul Gut in the Defiled Temple, a lethal-looking vertical drop in the Whispering Depths, an illusory wall and elevator in the Zhentarim Hideout, or a tunnel uncovered during Mayrina's rescue.

The most important mechanical distinction is whether the route asks you to fight, investigate, or prepare for movement. The Whispering Depths punishes careless traversal because the green-hued hole requires a safe descent. The Zhentarim Hideout rewards close inspection of the environment, while the Defiled Temple places access behind a hostile factional presence. These are different solutions to the same progression problem, so party composition can make one entrance feel more convenient than another.

Entering the Underdark is also a regional transition rather than the end of Act 1. The area supports its own exploration and character encounters, including the Myconid colony and the introductions to Blurg and Omeluum. Treat the objective as opening a new part of the campaign: reaching the destination advances the route, but it does not by itself resolve every Underdark quest or determine the party's final route to Moonrise Towers.

What works and what does not

Phases

1. 1

   Surface investigation

   Starts: The party begins searching the Act 1 overworld for a route below the surface.

   There is no single entrance marker that replaces exploration. Each route is found in a different local context, so inspect nearby rooms, tunnels, and story areas rather than following only the quest label.

   • Record which entrances you have already checked so you do not repeat the same search.
   • Resolve immediate hazards before treating an entrance as an easy transition.
2. 2

   Entrance obstacle

   Starts: The party reaches one of the four access points.

   The obstacle changes with the route. True Soul Gut and her key are associated with the Defiled Temple, the Whispering Depths requires a safe fall, the Zhentarim Hideout conceals an elevator behind an illusory wall, and the Overgrown Tunnel emerges from Mayrina's rescue storyline.

   • Hostile guardiansTell The route is watched by powerful enemies or faction agents.Answer Prepare the party before engaging and consider another entrance if the fight is not favorable.
   • Environmental descentTell The path drops through a green-hued hole.Answer Use Feather Fall or another reliable fall-protection method before jumping.
   • Do not use the same tactic for every entrance; identify whether the barrier is combat, traversal, or investigation.
3. 3

   Underdark arrival

   Starts: The party successfully passes through the chosen route.

   The destination is a large region with its own threats and story content. Arrival completes the route-finding purpose but begins further exploration rather than ending Act 1.

   • Orient the party and prepare before pushing deeper.
   • Look for the Myconid colony and its notable characters, Blurg and Omeluum.

Choices and consequencesSpoilers

• Enter through the Defiled Temple

  The party must deal with True Soul Gut and obtain a key, making this route dependent on how the temple encounter is handled.

• Jump through the Whispering Depths entrance

  The party can reach the Underdark through the green-hued hole, but an unsafe descent can cause severe injury or death.

• Use the Zhentarim Hideout

  The party can access a secret elevator behind an illusory wall, provided it can navigate the hideout and its Zhentarim presence.

• Follow the Overgrown Tunnel

  The route becomes available while progressing the effort to save Mayrina from Auntie Ethel, tying entry into the Underdark to that storyline.

• Use the Mountain Pass instead of the Underdark

  The party follows a different major Act 1 route. This page covers the Underdark path for parties that are not using the Mountain Pass.

Checklist

• Identify at least one of the four Underdark entrancesThe routes are the Defiled Temple, Whispering Depths, Zhentarim Hideout, and Overgrown Tunnel.
• Prepare healing and useful abilities before enteringThe destination is a dangerous region, not merely a short transition.
• Bring Feather Fall or another safe descent plan if using the Whispering DepthsThe green-hued hole can be lethal without protection.
• Search for the illusory wall if using the Zhentarim HideoutThe secret elevator is not presented as an ordinary open staircase.
• Obtain the Defiled Temple key if using that routeThe key is connected to True Soul Gut.
• Check whether the Overgrown Tunnel overlaps with your Mayrina objectivesThis route is discovered during the effort to save her from Auntie Ethel.
• Confirm that the party has arrived in the UnderdarkReaching the region is the core objective.
• Visit the Myconid colony when readyBlurg and Omeluum can be encountered there.

Failure conditions

• The party dies during an entrance encounterA hostile route can defeat the party before the Underdark transition. Revive or reload as appropriate, then consider a different entrance or a better-prepared approach.
• The party makes an unprotected descent through the Whispering DepthsJumping through the green-hued hole without Feather Fall or another safe method can kill characters or leave the group badly damaged.
• The party fails to obtain access in the Defiled TempleThe Defiled Temple route depends on dealing with True Soul Gut and obtaining a key; without that access, use another entrance.
• The party overlooks the concealed route in the Zhentarim HideoutThe elevator path is behind an illusory wall, so treating the hideout as a normal room-by-room dungeon can leave the route undiscovered.

Rewards

• Access to the Underdark
  Successfully completing one entrance route opens the Underdark as a major Act 1 region.
• Progress toward Moonrise Towers
  The Underdark serves as a primary route toward the wider Act 1 objective of reaching Moonrise Towers.
• Myconid colony encounters
  After arrival, the party can encounter Blurg and Omeluum in the Myconid colony.

AftermathSpoilers

Trivia

• The quest is unusual because four separate entrances lead to the same broad destination.
• The four routes are distributed across different overworld situations rather than grouped in one dungeon.
• The Underdark is treated as a primary Act 1 route for parties that do not use the Mountain Pass.
• The Overgrown Tunnel entrance links an underground travel objective with the effort to save Mayrina.
• The Zhentarim Hideout route emphasizes an illusory wall and secret elevator instead of a visible staircase.

Sources

• Baldur's Gate 3: How to Enter the Underdark — gameranx.com
• Community discussion of Underdark routes — reddit.com

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