Tenebris Somnia item locations are spread across six areas, and the floor you are on tells you what you are likely to be missing. Everything below is listed by the room it sits in, so you can walk straight to it.

Tenebris Somnia item locations, floor by floor

Floor 3 — Iván's apartment

  • Old Book on the living-room floor near the Bedroom door.
  • Empty Glass on the bedroom bedside cabinet near the lamp.
  • Developing Chemical in the kitchen refrigerator.
  • Wrench in the bathtub.
  • Green Candle from the writing on the Study wall.
  • TV Remote and the discharged Cellphone on the Study desk.
  • Save flame in the Study, on the left table as you come in.
  • Glass Vase on the Study table.
  • Empty Glass Box and the empty photograph frame on the right bedroom bedside table.
  • Chemicals on the table inside the sealed bathroom.
  • White Candle in the room opened by the Green Square Stone at the far right of the apartment, on the left bedside table.
  • Hexagonal Stone in the green-symbol bedroom's right bedside drawer, once you fill the empty photograph frame.

Ground-floor lobby

  • Bible on a table in the lobby, which is what starts a hidden ending run.
  • Apartment Key, which you are carrying from the first minute of the game.

Floor 2 — the apartment and the A.S. studio

  • X-Ray on the small bookshelf near the apartment entrance.
  • Scissor Blade on the kitchen counter.
  • Glove and Photographs on the Study clothes rack.
  • Revolver, ammunition and the first Film Canister in the chest in the Study.
  • One Battery inside the kitchen washing machine, after the Glove cuts the power at the fuse box, and one behind the bathroom shower curtain.
  • Blue Triangular Stone beyond the window of Sanguis's bedroom.
  • Save flame in the bedroom.
  • Silver Bottle in the locked cabinet beside the bathroom sink, opened with the Silver Key.
  • Glass Box on the bedroom bedside table.
  • Circular Plate, produced at the kitchen oven.
  • A.S. Key, freed from the A.S. door.
  • Second Scissor Blade on the Director's Office desk, with a save flame in the same room.
  • Six Cardboard Pieces, cut from the cardboard figures along the chair-lined corridor.
  • Devora poster in the Director's Office, with the Bathroom Key revealed behind it.
  • Mop Handle in the bathroom just left of the Director's Office door.

Floor 1 — the theater

  • Black Tape at the first landing of the dining-set staircase, near the door with a hook.
  • USB Adapter at the top of that staircase, beside the boarded door.
  • Screwdriver on the stairs up to the projector.
  • Photo Roll on the theater-lobby floor.
  • Plate with X in the first theater box.
  • Cow Skull in the second theater box.
  • Cold Chisel in the last theater box.
  • Save flame in the Floor 1 hallway.
  • The remaining theater chest, opened with the Tin Key, holds the Green Candle.

The bar

  • Four Bottles: one on the outdoor table outside, one on a table inside, one behind the counter and one in the Bathroom sink.
  • Iron Pipe fixed to the bar bathroom wall, removable with the Screwdriver.
  • USB Cable, after the pitcher puzzle.

Floor 0 — the film school

  • Photo Paper in the blue Screenwriting classroom.
  • Shotgun and the camera in the green Cinematography classroom.
  • White Bulb in the lamp of the red Photo Developing room.
  • Black Bulb in the blue classroom.
  • Piece of Cable in the Equipment Storage upper cabinet.
  • RCA Cable in the box under the collapsed mannequin.
  • Copper Seed taken from the blue bird in a camera scene.
  • Copper Poppy Flowers from the green vase upstairs in the hall.
  • Copper Key left on the chair in the camera room.
  • Black Candle on the desk in the dark TV room.
  • Save flame near the school stairwell.

Floor -1 and the endgame

  • Second Film Canister, beside Iván as a child.
  • Red Pentacle Stone, dropped by Fumus.
  • Silver Key, given by Sanguis in the Film Studio Lobby.
  • Yellow RCA Cable, the blue one after the colours invert in Desiderium.
  • Red Candle that falls from Julia's statue in Desiderium.
  • Glass Vase with Julia's blood.
  • Memento, made from Julia's Figurine, Iván's Figurine and the Glass Box.
  • Lapis Fictus Knife from Iván's statue in the Floor 2 apartment.
  • Melanosis Knife, transformed at the Floor 2 kitchen fuse box.
  • Viridis Knife, taken from the mercury pool beside the TV.
  • Lead Key from the hole at the TV's lower right.
  • Aurifer at the sealed hotel door.

The full list of where each key item sits is above, and the puzzles they open each have their own solution in the puzzle hub.

Key items that open the endgame

Four items decide the last stretch of the game: the Silver Key opens the cabinet with the Silver Bottle, the Red Pentacle Stone opens the two doors that lead to the moonlit window, the Lapis Fictus Knife is the base of the three knives the endgame needs, and the Aurifer itself is forged at the sealed hotel door once you expose it to moonlight.

The Silver Key and the Silver Bottle are covered in detail in the silver key guide, because getting them costs you three save points.