Case file
The Boiler Room Question: a free mystery logic-grid puzzle
Nobody disputes that something happened at the Boiler Room. Everything after that is disputed. What follows is only what I can prove.
This free Open and Shut logic-grid puzzle has 4 suspects, 4 locations, and 4 pieces of evidence. New to logic grids? Start with the mystery-solving guide.
This browser is not letting the site save anything, so your marks will be lost when you leave the page. Puzzle progress is not backed up or synced anywhere else.
How to mark the grid
- ●
- These two belong together.
- ✕
- These two are ruled out.
- blank
- Still undecided.
How to play
Click, tap or press Enter on a cell to cycle it: blank, then ● for a pairing you have confirmed, then ✕ for one you have ruled out. Nothing fills itself in — the deductions are yours to make. Use the arrow keys to move around the grid.
Fill obvious Xs does the bookkeeping only: for each ● you have marked, it crosses off the rest of that pairing's own row and column. It never adds a ●, never reads a clue, and never changes a mark you made.
On a narrow screen the grid scrolls sideways.
Every case has exactly one solution, and it is always reachable by deduction alone. Nothing here guesses for you, and Check will not tell you which mark is wrong.
What Margo can prove
- Ingrid Solheim was in the Lift House.
- Ingrid Solheim was found with the Cracked Snow Globe.
- Bridget Calloway was not in the Bell Tower.
- Bridget Calloway was not in the Ice Rink.
- Reuben Ashworth was not in the Bell Tower.
- Bridget Calloway was not found with the Missing Patrol Log.
- Bridget Calloway was not found with the Torn Canvas Tent.
- Reuben Ashworth was not found with the Missing Patrol Log.
The grid
On a narrow screen the grid scrolls sideways.
Result
Your marks, completions and streak are saved in this browser only. There is no account, and clearing your browser data clears that local progress. If you accept analytics, the site sends anonymous puzzle-usage events; it never sends your grid marks, clues or solution.
If you want sixty more, with the story
Five properties, five complete case files
Each Five-Star Mysteries volume holds 60 story-led logic-grid cases at one remarkable hotel or resort — the short mystery, the complete evidence, and one answer you can prove. Every volume stands alone.
-
Checkout Time
Volume one · Grand hotel
-
No Vacancy
Volume two · Desert resort
-
The Last Resort
Volume three · Island resort
-
Do Not Disturb
Volume four · Ski lodge
-
Lost and Found
Volume five · Grand spa hotel
Opens Amazon, who sell the books and set the final price.