- Black Ooze Puzzle: Located in Chapter 2, requiring players to separate ooze from water in a refinery.
- Refinery Power: Flip switches 1, 2, and 4 in the green fuse box to reach the required power level.
- Water Tank Goal: Move exactly four units of black ooze into the gold pipe on the left side.
- Piano Console: Use specific numeric sequences (1-2-4-5) to raise towers and (1-1-4-4) to rotate them.
- Statuette Filling: Requires both a "Liquid Tune" and a "Fire Tune" to successfully prepare the relic.
Activating the Refinery Power
The call of the elder gods black ooze puzzle represents one of the most significant mechanical hurdles in Chapter 2: Of Colossal Caves and Ancient Relics. Before you can interact with the complex machinery of the refinery, you must restore power to the chamber. This involves navigating the dock area as Harry and locating the green electrical box near the diving suit station.
Video Highlights:
- Visual guide to the Chapter 2 refinery layout.
- Step-by-step demonstration of the water tank separation.
- Piano console button sequences for tower manipulation.
- Final statuette filling process and exit strategy.
Once you reach the diving suit area, follow the yellow wiring to the green box. You need to interact with the switches to bring the gauge into the green zone. Each switch provides a specific increment of power, and finding the right combination is essential for the refinery's circular button to become active.
| Switch Position | Power Increment | Status for Solution |
|---|---|---|
| Switch 1 (Left) | High | ON |
| Switch 2 | Medium | ON |
| Switch 3 | Low | OFF |
| Switch 4 | Medium-High | ON |
| Switch 5 (Right) | Low | OFF |
If the switches above don't immediately work for your specific save state, try the alternative sequence of 2nd, 3rd, and 5th switches. The goal is simply to land the needle within the highlighted green arc on the gauge.
Solving the Water Tank Separation
After powering the room and stepping on the circular floor button, you are faced with the core of the call of the elder gods black ooze puzzle. The refinery consists of three tanks and a series of buttons. Your objective is to filter out the water so that only pure black ooze remains in the largest tank, which is then redirected upwards through the gold piping.
Initial Fill
Interact with the main console to fill the tanks. You will start with a mixture of water and black ooze distributed across the three containers.
Filtering Water
The buttons below the tanks allow you to move liquid between them. Your goal is to isolate the water. If the largest tank is sending over too much liquid, it will drain the black ooze you need.
Balance the Volume
Move one portion of water from the first tank into the third tank. This creates space to filter out the remaining water from the largest tank without losing the concentrated ooze.
Final Redirect
Once the largest tank contains exactly four units of pure black ooze, use the redirect command to send it up into the gold pipe. You will hear the Professor confirm that "something is happening up here."
Be careful not to accidentally purge the black ooze while trying to get rid of the water. If you lose too much ooze, you will have to reset the machine using the central reset lever to start the distribution over.
The Piano Console and Tower Manipulation
With the ooze redirected, the focus shifts to the "piano-like" control panel. This device controls the two massive stone towers in the center of the lake. To progress, you must raise these towers and rotate them so their doorways align with the walkways, allowing Harry to retrieve and prepare the ancient statuette.
Raising the Towers
- Tune: 1 - 2 - 4 - 5
- Action: Hit the first two buttons, skip the third, and hit the last two.
- Result: The towers emerge from the water, revealing hidden doorways.
Rotating the Towers
- Right Rotation: 1 - 1 - 4 - 4
- Left Rotation: 4 - 4 - 1 - 1
- Result: Aligns the doorways with the wooden platform for physical access.
The notation for these tunes can be found on the murals scattered throughout the cave. It is highly recommended to jot these down in your journal as you find them, as they are required for the final stages of the chapter.
| Command Type | Button Sequence | Purpose |
|---|---|---|
| Raise/Lower | 1, 2, 4, 5 | Toggles tower height |
| Rotate Clockwise | 1, 1, 4, 4 | Aligns Right Tower door |
| Rotate Counter-Clockwise | 4, 4, 1, 1 | Aligns Left Tower door |
| Liquid Filling | Found on Mural | Fills statuette with ooze |
| Fire Hardening | Found on Mural | Sets the ooze permanently |
There are five total murals in this area. The first is next to the Professor, the second is inside a small cave entrance to the right of the console, the third is past the diving suit, and the final two are inside the towers themselves.
Filling the Statuette and Achievements
Once the towers are aligned, enter the left tower to retrieve the statuette. You then need to take it to the right tower and place it into the specialized tube contraption. This is where you finalize the call of the elder gods black ooze puzzle by imbuing the relic with the processed fluids from the refinery.
To complete the ritual, return to the piano console and play the two new tunes you learned from the tower murals. The first tune handles the liquid injection, while the second tune applies heat. However, there is a secret achievement available here for those who experiment with the sequence.
| Achievement Name | Requirement | Reward |
|---|---|---|
| What an odd way of talking | Find the Peaslee voice recording | Bronze Trophy |
| Genius or Moron | Play the reverse Fire Tune (3-5-2-4) | Silver Trophy |
| Refinery Master | Complete the ooze separation on first try | Gold Trophy |
Before playing the standard fire tune, play the reverse: 3rd Button - 5th Button - 2nd Button - 4th Button. This freezes the statuette instead of heating it, unlocking the "Genius or Moron" achievement. You must look at the frozen statuette in the tower to trigger the notification.
Chapter 2 Progression Checklist
Before leaving the cave and heading back to the underwater bridge, ensure you have completed all necessary interactions. Missing a mural or a document now may require a tedious backtrack later in the game.
Essential Chapter 2 Tasks:
- Restored power to the refinery via the green fuse box
- Separated 4 units of black ooze in the water tanks
- Collected all 5 murals for the piano console tunes
- Found the Peaslee voice recording for the achievement
- Filled the statuette with liquid and fire tunes
- Sent the finished statuette to Evangeline via the dumbwaiter
After sending the statuette, Harry must return to the water. Interact with the diving suit to "Go Down." You will use the powered statuette to pass through the black ooze wall that previously blocked your path, leading to the end of the chapter.
Frequently Asked Questions
Q: How do I get exactly four units of black ooze?
Focus on moving the water units into the side tanks first. If you have a mix, move one unit of water to tank 3, then move the remaining water from the main tank. It requires balancing the volumes so the overflow doesn't take the ooze.
Q: The piano console isn't doing anything when I press buttons. Why?
You must press the large circular button at the bottom of the console after inputting the numeric tune (e.g., 1-2-4-5) to execute the command.
Q: Where is the key to the generator building in Chapter 4?
While this guide focuses on the Chapter 2 ooze puzzle, the Chapter 4 key is found in a lockbox on the ground floor of the radio tower, right next to the stairs.
Q: Can I fail the black ooze puzzle?
No, you cannot permanently fail. If you run out of ooze or make a mistake, use the reset lever on the right side of the refinery to refill the tanks and try the separation again.