Cthulhu: The Cosmic Abyss throws players into a cryptic world where progress hinges on patience and attention to detail. Early on, players face a ritualistic puzzle involving mystical stones that unlock a mysterious portal, establishing the tone for the game’s challenging and immersive atmosphere. This opening challenge isn’t just a barrier; it’s a perfect encapsulation of why this game demands your full detective instincts right from the start.
It’s worth remembering that this walkthrough is crafted to help you move through the chapter swiftly, but the game offers many additional clues and lore scattered throughout. Taking time to explore them enriches the experience and deepens your connection to the eerie story of Cthulhu: The Cosmic Abyss.
Cthulhu: The Cosmic Abyss – Chapter 1: The Awakening Walkthrough
Once the opening cinematic fades, your partner discovers the front door is securely locked. Your first objective is to find an alternate entrance. Head left and interact with the flower pot to learn how to examine objects and pick them up. Use the flower pot to clear the wooden obstruction by crouching and crawling underneath.
Progress onwards until you reach the second floor by climbing a fallen tree. Enter the house through the upper window and proceed to the bedroom on the right. There, a phone will be ringing—answer it to trigger the next sequence. Afterward, head downstairs to allow your partner inside and officially begin the chapter’s main puzzle.
Fixing the Occult Fresco
Within the dining room’s mysterious chamber, you'll encounter an Occult Fresco—a mural made from scattered pages on the wall. The image is fragmented, with pieces lying around the room. Your goal is to reconstruct this mural by collecting and placing the pages correctly.
- Take the paper on the table and slot it at the northern edge of the left circle within the mural.
- Use the sheet near the chair on the left side of the same left circle.
- Position the paper closest to the mural on the right side of the left circle.
- Place the sheet found in the center of the room on the left side of the right circle.
- Examine the receipt on the table; the back also forms part of the mural. Place it on the right side of the right circle.
Once completed, the mural will display two intersecting circles outlined with mystical symbols—an image that will soon become vital.
Completing this fresco unlocks the “Artist” achievement, which, while optional, provides important insight: the mural hints strongly that two specific stones will be required to move forward, setting you on the right path within the eerie house.
Finding the Stones
To investigate further, pick up any stone in the house to learn how to analyze materials using your sonar. Scanning reveals many mineral samples, but the mural guides you to exactly which two are significant.
The first key stone, called Basalt Rock, lies hidden behind the bed collapsed on the floor in the dining room. Add this to your inventory and continue exploring.
The second stone, a green mineral known as Fused Quartz, can be found sitting on a shelf inside the office. Both stones share the detail that they appear broken, distinctly setting them apart from other rocks scattered around the house. This observation can help deduce their importance without solving the mural puzzle fully.
Opening the Portal
With the stones gathered, descend to the basement and enter through the newly unlocked door. There you will find a mound of eerie green goop with two circular slots at its center. A cutscene precedes the puzzle’s resolution.
This gelatinous mass mimics the Occult Fresco’s pattern, signaling that these two stones must be inserted correctly. Place the Basalt Rock into the left slot, then the Fused Quartz into the right slot.
Once both stones are in place, the portal activates, allowing you to proceed. Watch the following cutscenes to conclude Chapter 1 and prepare for the greater mysteries ahead in Cthulhu: The Cosmic Abyss.
