Tenebris Somnia: Moonlight Puzzle Guide

Which moonlight step are you on?

Current item	Destination	Result
Bottle With Three Doses of Water	Hotel / vacation-room window beside Julia's statue	Purified Water
Viridis Knife	Hotel door with a strange keyhole symbol	Aurifer

The steps below follow published release-game routes. Names can differ slightly between localizations; identify the item and scene rather than copying a floor number without checking the building.

Silver Key and Silver Bottle

Interact with the cursed canister in the Film School until the sequence returns you to Sanguis. Exhaust his dialogue and select SPELL to receive the Silver Key and the book information. Use the key on the locked cabinet beside the sink in the second-floor apartment bathroom to obtain the Silver Bottle.

The bottle needs water from three different save points. Using it consumes those points, so choose before you start. Preserve a convenient Film School save for the return journey. This is a resource decision, not a normal refill you can repeat indefinitely.

Purify the water at the window

1. Check that the inventory item contains all three doses of water.
2. Obtain the red Pentacle Stone after the Fumus encounter. It opens the marked doors needed for this route.
3. Open the marked third-floor bathroom door and the white, red-marked door in the second-floor film-studio lobby.
4. In the hotel / vacation room, finish the dialogue and approach the window beside Julia's statue.
5. Use the filled bottle at the window. Confirm that the item becomes Purified Water.
6. Return to the cursed film canister in the Film School and use the water on it. Take the cleansed canister and return to the projector.

Published routes suggest different sets of three save points. The essential condition is three doses from different points; the precise suggested trio is not a universal puzzle code.

The later knife ritual

Show late-game crafting and route spoilers

The knife changes in order: Lapis Fictus → Melanosis → Viridis → Aurifer. Electricity and mercury come before moonlight. If your item is still Melanosis, return to the mercury stage first.

With the Viridis Knife and Lead Key, return through the hotel route. Use the key on the locked north door, continue to the save point and find the next door with the unusual keyhole symbol. Save, use the Viridis Knife at that door, then confirm the inventory now contains the Aurifer.

Keep this save separate. The Relicta choice after obtaining the Aurifer determines the two main ending routes. Read the ending conditions before attacking them.

Why nothing happens

• The bottle is not full: check the item description for three doses.
• The window is inaccessible: finish the Fumus and Pentacle Stone progression rather than searching the opening apartment window.
• You have a knife at the statue: this is the bottle location. The late ritual uses the marked door.
• The knife has the wrong name: complete the preceding transformation first.

Return to the walkthrough for the surrounding route.

Sources

• Prima Games: Silver Key and Purified Water.
• Into Indie Games, Part 2 and Part 4: window and knife destinations.

Checked October 23, 2026 against the linked written routes; these are not claims of an in-game test by this site.