The Tenebris Somnia bottle puzzle is a sound puzzle behind the bar: you fill a large glass pitcher until its tone matches the counter bell, then shatter it and take the USB Cable inside. The amount of liquid needed is randomized every playthrough, so the method matters and the answer does not.

Where the bottle puzzle happens

The bar holds a large glass pitcher and a counter bell. Four Bottles are needed to fill and empty it:

  • one on the outdoor table outside the bar,
  • one on a table inside,
  • one behind the counter,
  • one in the sink of the bar Bathroom.

The other item you want here is the Iron Pipe, which is fixed to the bar bathroom wall. It only comes loose once you have the Screwdriver, which is found on the stairs up to the projector on Floor 1 — so come back for the pipe after that, not before. Where every bottle and every other bar item sits is in the item locations list.

Matching the pitch to the bell in the Tenebris Somnia bottle puzzle

  1. Ring the counter bell and listen to its pitch. Memorize that note; it is the reference for the whole puzzle.
  2. Use a Bottle at the large glass pitcher to add liquid.
  3. Strike the pitcher with your Wrench and hear the tone it makes.
  4. Compare the two notes. If the pitcher's tone is too low, add more liquid with a Bottle; if it is too high, use an empty Bottle at the pitcher to take liquid back out.
  5. Raise and lower the level until the pitcher's tone matches the bell.
  6. Ring the bell. The glass shatters.
  7. Strike the cracked pitcher and collect the USB Cable.

Because the required liquid amount is randomized for every playthrough, there is no fixed number of bottles and no fixed combination. Work up and down against the bell's note rather than expecting a published answer.

What the USB Cable unlocks

The USB Cable is the item the Floor 1 puzzle needs.

  1. Take the USB Adapter from the top of the dining-set staircase.
  2. Combine the Adapter with the Cable to make the USB Charger.
  3. Use the Charger on the discharged Cellphone in the Floor 3 Study.
  4. Read the four-digit code on the phone screen. The Old Book records the same code.
  5. That code opens the Floor 1 projector room, which is where the first Film Canister is played.

The route from that room to the finale is in the walkthrough.