The Tenebris Somnia Cold Chisel sits in the last theater box on Floor 1, and it opens the boarded door at the top of the dining-set staircase. Here is the whole chain in order, from the tool to the Hexagonal Stone:

  1. Cleanse the third Film Canister. The Cursed Film Canister in the Film History classroom only becomes the third canister once you use Purified Water on it, and that step is on the moonlight page.
  2. Play the third canister at the Floor 1 projector. The last theater box opens.
  3. Take the Cold Chisel out of that last theater box.
  4. At the top of the dining-set staircase, use the Cold Chisel plus a melee hit to remove the boards on the boarded door.
  5. Past the boards a hallway leads to the final film set, where a shelf has to be pushed out of the way.
  6. Inside the final film set, use the White Bulb on the blood-covered table to make the Red Light Bulb.
  7. Leaving the set triggers a cutscene and an ambush wave. One strike from the pipe takes the wave down, and that wave fight behind the Cold Chisel door is Carnitos — the boss guide has the no-damage route.
  8. The Red Light Bulb then drives the photo puzzle in the Photo Developing room, and the developed Photo opens the Floor 3 bedside drawer with the Hexagonal Stone. The photo puzzle page has the darkroom steps.

Where the Cold Chisel is

The theater is on Floor 1 and it has three boxes along the wall. The last one opens when you play the third, cleansed Film Canister at the Floor 1 projector. The projector needs its four-digit code, which you read off the discharged Cellphone in the Floor 3 Study with the USB Charger; the Old Book records the same code. The route that gets you the USB Charger and the canister is in the walkthrough.

How to open the boards

The boards are at the top of the dining-set staircase on Floor 1. Equip a melee weapon, use the Cold Chisel on the boarded door, then hit it once. The Chisel alone does not drop them — the melee weapon is what does the damage.

What is behind the boards

A hallway leads to the final film set, and a shelf in the way has to be pushed aside. Inside the set, use the White Bulb on the blood-covered table to make the Red Light Bulb; the White Bulb sits in the lamp of the red Photo Developing room on the film school's ground floor.

The photo puzzle and the Hexagonal Stone

The Red Light Bulb is the first half of the photo puzzle: it goes in the lower-left lamp of the Photo Developing room, and the print you develop from it opens the Floor 3 bedside drawer with the Hexagonal Stone. The photo puzzle page has the darkroom steps with the item location for every ingredient.

If you are stuck

  • The last theater box stays shut. The third canister has to be the cleansed one — use Purified Water on the Cursed Film Canister first, and only pick it up after that.
  • The boards do not fall. Equip a melee weapon, use the Cold Chisel on the door, then hit the boards.
  • A bulb is missing. The White Bulb is in the red Photo Developing room on the film school's ground floor. Every item on this chain is listed on the item locations page.