Room 12 needs a detective. Turn your sound on.

Lessons you need for this case

The six notes in this case use six different secret codes. You must have finished all six code lessons to solve the whole mystery. If you skipped one, go back and learn it now.

Check the box next to each lesson you have finished.

    Check all six lessons to open the case.

    How this case works

    1. Read about the case and hear the eight theories.
    2. Crack the six notes. Each one is written in a different code, and nobody will tell you which code is which.
    3. Answer three questions. What is he really doing in the closet? Why is it a secret? Who is his secret helper?

    Be careful with step 3. A wrong answer locks the answer box for 3 minutes. Guessing will not work. Cracking the notes will.

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    Teacher note

    Answers are inside. Enter the teacher password.

    What is going on

    For three weeks, the same strange thing has happened in Room 12. At 11:45, Mr. Lehmkuhl picks up his lunch, walks into the supply closet at the back of the room, and shuts the door.

    He stays in there for forty minutes. He comes out at 12:25, smiling, and says nothing about it.

    Nobody has been hurt and nothing is missing. But the whole class is going bananas trying to figure out why. This case has no robber. It has a riddle.

    What we know

    The closetIt is a plain supply closet with one light bulb. He locks the door from the inside.
    The soundsClack, clack, clack. Then a ding. Then more clacking. Sometimes he laughs out loud.
    What goes inA lunch bag. Lettuce. Stacks of paper. And three weeks ago, a heavy black case with a handle.
    The notesSix notes have turned up near the closet. All six are in strange writing, in the same dark blue pen.
    A wrapperOne peppermint wrapper, found on the floor by the closet door.

    Marcus says: "It is so easy. Secret room. Secret noises. Secret notes. Our teacher is a SPY. Somebody write that down."

    The timeline

    • Three weeks ago, Monday. Mr. Lehmkuhl carries a heavy black case into the closet. He eats lunch in there for the first time.
    • That same week. He asks Mr. Sweep for 200 sheets of paper. He stops eating the lunchroom meatloaf.
    • Two weeks ago. The clacking starts. So do the theories.
    • This week. Sticky notes start turning up near the closet door.
    • The last day before break. Mr. Lehmkuhl has told the class, "I will have a surprise for you."
    Words to know: clue and theory. A clue is something you really saw or heard. A theory is your guess about what the clue means. A clue can be true even when the theory is wrong.

    Eight people, eight ideas

    Everybody has a clue, and almost everybody has a theory. Keep the two apart in your head. Ask yourself: is the clue real? Does it really prove the theory?

    Marcus says: "You can read all eight if you want. But only one of them explains the DING. Mine."

    The six notes

    Every note has a secret message. First work out which code it is. Then crack it. The keys are in the Code toolkit tab. You need all six notes to answer what, why, and who.

    Notes cracked: 0 of 6

    Number Code Review the lesson

    Every letter has a number. A is 1, B is 2, C is 3, and so on, all the way to Z, which is 26. Find each number in the table. The letter is right above it.

    Atbash Cipher Review the lesson

    Atbash is the mirror alphabet. A swaps with Z. B swaps with Y. C swaps with X, and so on. Look up each code letter on the top row. The real letter is right under it. It works the same way in both directions.

    Rail Fence Cipher Review the lesson

    The letters are not changed. They are written in a zigzag on the rails of a fence, then read one rail at a time. Here is HELLO WORLD on two rails.

    H . L . O . O . L . . E . L . W . R . D

    Read the top rail, then the bottom rail, and you get the code: HLOOL ELWRD. To crack one, count the letters and split them into a top rail and a bottom rail. If the count is odd, the top rail gets the extra letter. Then zigzag: top, bottom, top, bottom.

    Spartan Scytale Review the lesson

    The letters are not changed. They are only mixed up. The message was written on a strip of paper wrapped around a rod. Wrap the strip around a rod of the same size and the words line up again.


    Read across each row, starting at the top. If the rod is the wrong size, you get nonsense.

    Hidden Message Review the lesson

    A hidden message does not look like a code at all. It looks like a normal, boring note. The secret is hiding in the first letter of each word. Write down those first letters, in order, and read what they spell.

    Example: "Please ask Sam soon" hides the word PASS.

    Pigpen Cipher Review the lesson

    Each letter is drawn as the shape of the pen around it. Shapes from the second grid and the second X have a dot. Use this key for this case.