- Mental Lock #1
- Mental Lock #2
- Mental Lock #3
- Mental Lock #4
- Mental Lock #5
In the fourth chapter of Mizuki’s route in AI: The Somnium Files – Nirvana Initiative, you’ll need to enter the mind of the elusive Tearer, the game’s primary antagonist. Inside their psyche, you’ll be faced with numerous numerical challenges that reveal more of the character’s backstory and involvement with the Half Body Serial Killings.
This particular somnium requires you to unlock five mental locks. Most of these mental locks are based around escape room style puzzles, with plenty of maths thrown in for good measure. It represents one of the game’s more challenging sets of puzzles in terms of difficulty, but can be overcome with some carefully considered strategies.
Mental Lock #1
After you enter the somnium, which appears like an abandoned factory, you’ll encounter many details, but as Aiba states, you can only interact with the purple and green sphere in the centre of the room. Move over to it and choose to interact with it.
After this, you’ll need to look around the room with other objects to interact with to gain more information. Move over to the computer at a desk labeled PC1 and interact with it. The screen says R enter, so choose to press the enter button when given the option.
You’ll soon find yourself in an ‘escape room’, which can seem overwhelming at first. There’s a key equating symbols to particular letters on the wall, then a variety of doors with both colours and symbols on.
Before you do anything, inspect the paper on the ground to find this useful code-breaking device, which has each letter equated to a specific number. This will be used later. After picking up the chart (which you can now check by pressing a shoulder button), the sphere from earlier will reappear in this room.
Don’t touch the sphere, or you’ll receive a time penalty.
Now you’ll be able to freely roam around the escape room and interact with all the elements. The first thing you’ll need to do is ‘solve’ all the equations on the walls using your chart.
Do this by looking at the chart and identifying the number associated with each letter, then doing the equation on the wall, which will be either simple addition or subtraction. All of these will have a single-digit solution:
- N (3) + A (6) = 9
- I (43) – X (39) = 4
- T (55) – R (52) = 3
- U (72) – E (65) = 7
After solving the wall equations, you can now see an extra clue on the back of a blue person that has just appeared inside the sphere. It’s the letter O inside a star shape.
Note that all of the coloured lockers have a set of symbols on them. As with the letters on the wall, these symbols on the lockers also have another code associated with them: the solutions to each of the wall equations that you just solved. However, it may surprise you to learn that these answers we just put on the wall aren’t just numbers. When viewed from a certain angle, they can also be read as letters. This logic must be applied to the process of opening all of the lockers.
Head to the purple locker first to see a triangle, a star, and another triangle.
The solution to the third equation was the number three, which we can now see on the wall inside a triangle. If you note the line on the left side of the triangle, this indicates how the number might be viewed as a letter. If this were the bottom edge of the triangle, the three would appear like the letter M. We also know the star contains the letter O, so the three-letter answer to opening this locker is MOM. Opening this locker will give us the number 2 in return, which we can save for later.
The green locker requires you to input four letters. Once again, we must closely observe the symbols to see how these numbers might be interpreted as letters from a certain angle. Notice the lines on the symbols in the locker to see how the 4 in the square could be rotated to look like the letter H, the 3 in the triangle could also be seen as the letter E, the 7 in the circle can be made to look like an L, and the 9 in the hexagon can be made to look like a P. This gives us the word HELP to put into the locker, opening it up and revealing the number 1.
The yellow locker needs only two letters made from the triangle in two different configurations. The answer is ME. This will open up the locker revealing the final number, 5. You can now head to the door with three colours on and put in three digits corresponding to the three numbers you found in the locker of each colour: 215.
Behind the door is a piece of paper, a diary entry from Tearer. This will unlock the first mental lock.
Mental Lock #2
Follow the blue figure floating in the sphere and interact with it, then head upstairs to interact with the newly turned-on PC that says G enter. Once again, you should press enter.
You’ll be plunged into another room and given another puzzle to solve. This time, you’ll be in a room which has walls that phase in and out of existence as you move through them. If you move through a wall it will disappear, but if you move back through it, it will reappear.
The objective is to get the coloured rings in the room to line up with stained-glass paintings on opposing walls by removing the correct walls in the room. The space between the coloured ring and the stained glass must be unobstructed, as looking through the ring at the glass will show you a number that you’ll need to exit the room.
After doing the first ring, you’ll start to be chased by a sphere that will give a time penalty if it touches you. With this in mind, you must now move around quickly, but also carefully so as to make sure the correct walls are removed. Try to think of the room as a grid structure and consider the necessary route to create an unobstructed view for the rings.
After finding three of the rings, you can now exit the room by entering the three numbers found from each ring: 229. This will open the door, giving you another diary entry revealing the Tearer’s backstory and unlocking the second mental lock.
Mental Lock #3
You’ll be returned to the main room. Interact with the sphere again, and a third computer will turn on. As always, press the enter key to be transported to another puzzle room.
Interact with the book in the middle to make clocks appear on the wall. You’ll also receive a cryptic message, which is the key to solving this room’s riddle: “Add your half body to make an arrow.”
Head to the clock displaying the time 1:15. Think about how you could make a directional arrow appear on the clock by adding another hour hand on the opposite side of the one currently there. Now think about which direction this arrow would be pointing: left. Interact with the button next to the clock and then press ‘left’ to produce an arrow on its screen.
Now repeat this process for the other clocks. The clock displaying 10:00 could be transformed into a downward pointing arrow, so press down. The clock displaying 7:45 could be transformed into a right arrow, so press the right button. Completing this will give you a number to remember for escaping this room.
Now, a new book will appear on the ground, giving us the word MOTH as a clue. This actually related to the number chart we found earlier in the somnium, so open that up to see that M, O, T and H are all closely placed next to each other on the chart. In fact, they can be understood to represent one of the cardinal directions each. M is left, O is right, T is down and H is up. Press the correct direction to spell out MOTH on the four buttons in the room in clockwise order: left, down, right then up. This will give you another number.
The next book will appear on the ground, but this time, it will straightforwardly tell you which order to press the directions in – up, right, up, left, right. This will give you another digit in return.
Now we have all three numbers, we can leave the room by putting in the code 999, which will give us another menacing diary entry and unlock the third mental lock.
Mental Lock #4
Back in the main room, you can interact with the sphere one more time. Aiba will note that the mark on the wall has changed to say R x G x B.
This is actually an equation where each letter refers to the final three number code at the end of each section of the somnium thus far. Multiply these together to get the number 49185765, then run this through our letter-to-number chart that we received earlier, and it’ll spell out the word LOVE. When you interact with the sphere, they’ll ask what it is the Tearer truly wants, and you can type in the answer.
Mental Lock #5
Much like the previous mental lock, this one will require further use of the chart and some light mathematics. The mark on the wall will change to say R + G + B but mirrored.
The numbers on the mark on the wall are reversed, so we have to reverse the R, G, and B numbers here too. Adding these together (999 + 922 + 512) gives us the number 2433. Put this through the chart, and you’ll get the letters JIN. Putting this in will unlock the final mental lock and complete the somnium.
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