Puzzle 104 is Undercover Code, a 40-picarat Write Answer puzzle in Dalston Parlor in Monte d'Or, in Chapter 7. It's a hidden puzzle: nobody hands it to you, and you find it by searching a book on the bookcase. A famous writer's adventure novel has no page numbers, but its foldout island map holds a code that tells readers how many pages the book has. You crack the code and write down the number.
This page covers story Puzzle 104 in Professor Layton and the Miracle Mask, the 3DS game (US and UK English). The book and the answer are the same in the US and UK English versions, and the UK version calls the puzzle A Cracking Read; quotes use the North American text. If you're after Daily Puzzle 104 or Puzzle 104 from another Layton game, see Wrong Puzzle 104? below.

What Puzzle 104 is
| Name | Undercover Code (US), A Cracking Read (UK) |
|---|---|
| Type | Write Answer |
| Picarats | 40 |
| Location | Dalston Parlor, Monte d'Or |
| Chapter | Chapter 7 |
| How you start it | Search the books on the bookcase on the left of the room (hidden puzzle) |
| Required? | No |
| Previous puzzle number | Puzzle 103, Stars of the Stage (Big Top) |
| Next puzzle number | Puzzle 105, Free Lunch! (City Monument) |
The puzzle reads: "A famous writer has written an adventure novel with no page numbers. Apparently, the foldout island map contains a code that allows readers to work out how many pages are in the book." Then it asks: "Can you crack the code?" The objective bar says "How many pages?"
The top screen shows the book with its map opened out. The map is covered in odd, angular symbols that don't look like anything on their own. The touch screen has three boxes. Write one digit in each box and submit your answer.
Puzzle names
| Version | Puzzle name |
|---|---|
| North America | Undercover Code |
| UK | A Cracking Read |
| Japanese | 本の暗号 (Hon no Angō, "the book's code") |
The UK version calls the puzzle A Cracking Read. Its text also writes "fold-out" instead of "foldout", and Hint 3 is worded differently. The book and the answer are the same in the US and UK English versions.
Wrong Puzzle 104?
- Daily Puzzle 104 is Ducks 04, from the Little Lost Ducklings set.
- Puzzle 103, Stars of the Stage, is the puzzle before this one, in the Big Top. If yours has two star-shaped stages and cameras, that's the one you've got.
- Puzzle 105, Free Lunch!, is the next puzzle, at the City Monument. If yours is about a spinning wheel and who pays for lunch, that's the one you've got.
- Puzzle 104 in another Layton game is a different puzzle. If yours doesn't show a book with a foldout island map, you're in the wrong game.
Where you find it
Chapter 7 takes place on the fourth day of the investigation in Monte d'Or. Go into Dalston Parlor, the reception room in Dalston's mansion, and search the books on the tall bookcase on the left side of the room. Layton says, "This book holds a hidden puzzle," and the puzzle starts.

You don't have to solve it to move on. The puzzle stays in the bookcase until you solve it.
When the code gets confusing
- The symbols don't look like anything. They aren't meant to on their own. Open Hint 2 if you need a nudge.
- You're not sure how many digits to write. There are three boxes, and Hint 1 confirms it's a three-digit number.
- The game says "Too bad." The wrong-answer message is "Too bad. You're looking for a number. What looks like a number on that map?" You can try again.
- You can't find the puzzle. Nobody offers it. Search the bookcase on the left side of Dalston Parlor.
Hints, one at a time
These are the game's own hints, word for word from the North American version and in the same order. Open only the next one you need. In the game, Hints 1 to 3 cost one hint coin each and the Super Hint costs two.
Hint 1: the symbols
Those symbols on the map must somehow tell you the number of pages.
It's a three-digit number, by the way.
Hint 2: the folds
How would the foldout island map look if you folded it along the folds?
Hint 3: try another angle
If you fold up the map, you'll see something that looks more like numbers at some point. Maybe you should try rotating the book?
Super Hint: more than the map
You need to look at more than just the map. Numbers will become apparent when you put the folded map together with the cover of the book.
From the left, it should read 7, 3, and...
Answer and full solution
The answer below gives the number of pages, explains how the code works and shows the finished puzzle. Open it when you're ready.
Show the answer
Answer: 735. Write 7, 3 and 5 in the three boxes and submit.
- Fold the island map back up along its fold lines.
- Put the folded map together with the front cover of the book. Map and cover now make up the code between them.
- Turn the book round, as Hint 3 suggests. Read from the left, the code shows the digits 7, 3 and 5.

The game confirms it: "Correct! There are 735 pages in the novel. The key is to fold the map along the fold lines and combine it with the front cover. How novel!"
If it still doesn't work out:
- You read the digits from the map alone. The map isn't the whole code. The front cover is part of it too.
- The game didn't read your writing. Write each digit large and clear in its own box, and check the boxes before you submit.
Picarats, hints and hint coins
Undercover Code shows 40 picarats when it starts. The puzzle can award 40, 35 or 30 picarats. Wrong answers may reduce the picarat value. A wrong answer brings the message "Too bad. You're looking for a number. What looks like a number on that map?" When you search the bookcase again, Layton says, "An enigmatic book puzzle." before the puzzle starts again.
Hints cost hint coins, not picarats. Hints 1 to 3 cost one hint coin each and the Super Hint costs two, five in total. The hints on this page are free to open.
Does it unlock anything?
It doesn't give you an item. You get the picarats, and the puzzle counts toward your total.
Versions
- Nintendo 3DS family: this page covers the 3DS game. The book is on the top screen, and you write the number on the touch screen.
- US and UK English versions: the book and the answer are the same in the US and UK English versions. The UK version calls the puzzle A Cracking Read and words Hint 3 differently.
The scene around the puzzle
If you quit the puzzle, Layton says, "Perhaps another time."
When it's solved, Layton remarks, "I'm not entirely sure why the author decided to go in this direction."
FAQ
Where is the answer to Puzzle 104?
It's in the Answer and full solution section above, hidden until you open it. If you only want a push, open the hints one at a time first.
What is Puzzle 104 called?
Undercover Code in the North American version and A Cracking Read in the UK version. In Japanese it's 本の暗号.
Where is Puzzle 104?
In Dalston Parlor in Monte d'Or, in Chapter 7. It's a hidden puzzle: search the books on the bookcase on the left side of the room.
Do I have to solve Puzzle 104?
No. The story doesn't need it, and you only find it by searching the bookcase.
Can I fail Puzzle 104?
Yes. A wrong number brings "Too bad.", and you can try again as many times as you need. Wrong answers may reduce the picarat value.
How many picarats is Puzzle 104 worth?
It shows 40 picarats when it starts. The puzzle can award 40, 35 or 30 picarats. Wrong answers may reduce the picarat value.
Is Daily Puzzle 104 the same as Puzzle 104?
No. It's a different puzzle, listed under Wrong Puzzle 104?. Story Puzzle 104 is the hidden book puzzle in Dalston Parlor.
More Miracle Mask puzzles
- Puzzle 103: Stars of the Stage
- Puzzle 105: Free Lunch!
- Puzzle 102: Dice Crates
- Puzzle 101: Wonky Wiring
- Puzzle 098: Watertight Code
- Puzzle 100: Gate to the Ruins!
- Puzzle 60: Dangerous Holes
- Puzzle 113: Chip Champions
- Puzzle 118: Evenly Matched 3
- Puzzle 122: Kitty Solitaire 3
For the rest of the game's puzzles, see the Miracle Mask puzzle index.