# 1. CONCEPT LOCK ### Premise > **FINAL NIGHT NOTICE — VAULT 3B** > At 08:00 tomorrow, this branch becomes rubble. Officially, every deposit box has been cleared. Unofficially, the old vault ledger contains one number that never appeared on any customer statement: a box reserved for transactions the bank preferred not to record. The demolition crew has been told not to ask questions. You have forty-five minutes before the building’s final security cycle begins, and sixty before the vault records are considered permanently lost. Everything the last vault officer left behind is still in this room. Find the unlisted box, reconstruct its authorization code, and open it before the bank’s last secret disappears with the walls. **Win condition:** Open the locked cash box representing the unlisted deposit box and recover the printed **VAULT 3B — CLOSED ACCOUNT** certificate inside. ### Three recurring motifs 1. **Four-digit account numbers** — documents repeatedly use four-position identifiers, conditioning players to recognize ordered digits. 2. **“What the bank records / what the bank hides”** — ordinary print provides one layer; UV, omissions, or discrepancies reveal another. 3. **Closing procedure** — every puzzle uses bank language such as *balance, reconcile, authorize, audit, branch, ledger,* or *close*. **Build assumption:** the two supplied padlocks are resettable **3-digit combination padlocks**. Set them to **317** and **642**. If the actual padlocks use a different format, retain the puzzles but map their three-digit answers to the available locks. --- # 2. PUZZLE CHAIN MAP The design uses six puzzles. Puzzles 1–2 are deliberately accessible; Puzzle 3 is the midpoint difficulty spike. From Puzzle 3 onward, the team benefits substantially from dividing work between sales-oriented readers/pattern spotters and engineering-oriented logic/checking players. | # | Puzzle | Type | Physical interaction | Exact solution and answer | Unlocks | Est. / cumulative | | - | ----------------------------------------------------------------------------------------------------------------- | --------------- | ----------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------ | ----------------- | | 1 | **Closing Balance** — Find the three ledger entries that fail the bank's own reconciliation rule. | Observation | A printed “Final Teller Ledger” posted openly beside the whiteboard | Each row shows Deposit + Interest = Closing Balance. Three rows are deliberately wrong. Their transaction IDs, read top-to-bottom, end in 3, 1, 7. Answer: **317** | Padlock A, securing the “Night Audit Packet” | 4 min / **4** | | 2 | **Invisible Ink Department** — The audit packet tells players where the bank kept information it would not print. | Physical search | UV torch + the Night Audit Packet + documents already around the room | Packet contains “THE OFFICIAL COPY IS CLEAN.” Under UV, three documents carry the words “SIX / FOUR / TWO” beside numbered approval stamps. Reading stamp order 1→3 gives **642** | Padlock B, securing the “Exception File” | 6 min / **10** | | 3 | **Exception Account** — Determine which of six anonymous accounts satisfies every surviving vault restriction. | Logic grid | Printed Exception File, six account cards, whiteboard | Constraints eliminate five accounts. Only account **5831** satisfies all conditions. Answer: **5831** | Identifies which account card to turn over; its reverse contains the next instruction | 10 min / **20** | | 4 | **Four Eyes Authorization** — Reassemble four approval fragments in the order the bank requires. | Assembly | Four printed authorization slips from the Exception File; whiteboard optional | Account 5831 reverse says “NO TRANSFER CLEARS UNTIL FOUR OFFICERS SIGN IN SENIORITY ORDER.” Each slip gives a tenure number. Order 12, 9, 6, 2 years. Aligned fragments form **NORTH WALL** | Directs players to the document posted on the north-facing/marked “NORTH” side of the whiteboard | 8 min / **28** | | 5 | **After-Hours Recording** — Extract four numbers from the branch’s final security announcement. | Audio | Bluetooth speaker + printed “Security Call Log” found at NORTH WALL | Audio contains four short announcements. Log says “Record only calls made after closing.” The posted branch hours define closing as 18:00. Calls at 18:07, 18:22, 18:31, 18:46 contain spoken digits 4, 9, 2, 6. Answer: **4926** | Selects numbered columns 4, 9, 2, 6 on the final audit sheet | 7 min / **35** | | 6 | **Final Reconciliation** — Use everything the bank has authenticated to derive the deposit-box combination. | Arithmetic | Final Audit Sheet, previous answers, whiteboard, cash box | Sheet explicitly gives: “Exception Account 5831: take digit 1; Night Audit 642: take digit 2; Security Record 4926: take digit 3; Closing Balance 317: take digit 3.” This yields 5,4,2,7 → **5427** | 4-digit cash-box dial; inside is the closing certificate | 10 min / **45** | ### Puzzle 3: exact logic-grid contents Give players six account cards: | Account | Opened | Officer | Balance band | Access | | -------- | --------- | ------- | ------------ | ------- | | **2746** | Monday | Vale | Low | Morning | | **5831** | Wednesday | Chen | High | Evening | | **8194** | Friday | Vale | Medium | Evening | | **3652** | Wednesday | Ortiz | Medium | Morning | | **7418** | Monday | Chen | High | Morning | | **9263** | Friday | Ortiz | Low | Evening | The Exception File contains these five rules: * “The unlisted account was **not opened Monday or Friday**.” * “Its last authorized access occurred **after 17:00**.” * “Officer **Ortiz never handled high-balance accounts**.” * “The unlisted account was a **high-balance account**.” * “Officer **Chen handled the only Wednesday account accessed in the evening**.” Only **5831** survives all five constraints. ### Puzzle 5: exact audio script The speaker recording should sound like a clipped automated bank/security log: > “17:42. Loading entrance. Inspection code: eight.” > “18:07. Vault corridor. Inspection code: four.” > “18:22. Records office. Inspection code: nine.” > “17:55. Teller floor. Inspection code: one.” > “18:31. South stairwell. Inspection code: two.” > “18:46. Vault antechamber. Inspection code: six.” The Security Call Log states that branch closing time is **18:00** and that only *after-hours inspections* are entered into the vault record. Thus the unique extraction is **4926**. --- # 3. LAYERED CLUE STRUCTURE For Puzzle 1, there is necessarily no preceding puzzle; its Layer 2 is the starting instruction delivered with the premise. Thereafter, every Layer 2 is produced by the previous solve. ### Puzzle 1 — Closing Balance **Layer 1 — Ambient:** The Final Teller Ledger is visible from entry. Its footer reads, “A branch closes only when every line balances.” **Layer 2 — Unlocked/start:** The entry briefing says that the final vault officer “left the books unreconciled.” **Layer 3 — Confirming:** Exactly three rows fail the printed equation, and their final ID digits produce a three-digit number matching Padlock A. **Essential layer:** **Layer 1.** It contains both the operation and the data needed to solve the puzzle. ### Puzzle 2 — Invisible Ink Department **Layer 1 — Ambient:** UV torch is visible from the start, and ordinary documents bear approval-stamp boxes numbered 1–3. **Layer 2 — Unlocked:** Padlock A releases the Night Audit Packet containing: “THE OFFICIAL COPY IS CLEAN. CHECK WHAT THE LIGHT REVEALS.” **Layer 3 — Confirming:** Exactly three UV words appear beside the numbered approval stamps, and they spell number words rather than ambiguous symbols. **Essential layer:** **Layer 2.** It explicitly tells players to use the UV torch; Layer 1 merely foreshadows it. ### Puzzle 3 — Exception Account **Layer 1 — Ambient:** The whiteboard has a permanent-looking heading: “EXCEPTIONS MUST SATISFY **ALL** CONTROLS.” **Layer 2 — Unlocked:** Padlock B releases the Exception File containing the six account cards and five constraints. **Layer 3 — Confirming:** Applying every condition leaves exactly one account; its reverse uniquely contains printed material while the other five backs say “STANDARD ACCOUNT.” **Essential layer:** **Layer 2.** All information required for the deduction is inside the Exception File. ### Puzzle 4 — Four Eyes Authorization **Layer 1 — Ambient:** Four officer names and their tenure figures appear incidentally on a posted “Staff Authorization Register.” **Layer 2 — Unlocked:** Reverse of account **5831** says: “NO TRANSFER CLEARS UNTIL FOUR OFFICERS SIGN IN SENIORITY ORDER.” **Layer 3 — Confirming:** Correctly ordering and aligning the four slips produces clean, uninterrupted lettering reading **NORTH WALL**; wrong orders visibly break the letters. **Essential layer:** **Layer 2**, together with tenure values printed again in small type on the slips themselves. The ambient register is redundant. ### Puzzle 5 — After-Hours Recording **Layer 1 — Ambient:** A printed branch-hours notice states “Public closing: 18:00.” The Bluetooth speaker is already present. **Layer 2 — Unlocked:** At **NORTH WALL** is the Security Call Log: “Only calls occurring after public closing enter the vault record. Play FINAL SECURITY LOG.” **Layer 3 — Confirming:** Four—and only four—recorded timestamps occur after 18:00, matching the four extraction boxes printed on the Call Log. **Essential layer:** **Layer 2.** It repeats the 18:00 closing time, so missing the ambient notice cannot strand the team. ### Puzzle 6 — Final Reconciliation **Layer 1 — Ambient:** The cash box is visible throughout, with a four-digit dial and a label reading “UNLISTED DEPOSIT — FOUR AUTHORIZATIONS REQUIRED.” **Layer 2 — Unlocked:** Using **4926** on the numbered columns of the Security Call Log reveals: “FINAL AUDIT — USE AUTHENTICATED RECORDS IN THE ORDER PRINTED.” **Layer 3 — Confirming:** The Final Audit Sheet has four extraction boxes, and each requested source has already produced exactly the expected number of digits. **Essential layer:** **Layer 2.** It contains the complete extraction instructions; previous answers provide the source data. --- # 4. RED HERRINGS Exactly three are included. Each is conspicuously dismissible once inspected carefully. | Red herring | Appearance | Why tempting | Typical cost | Soft tell | | --------------------------- | -------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------- | -----------: | --------------------------------------------------------------------------------------------------------------------------------- | | **Demolition Invoice 8041** | Professional-looking printed invoice with a bold four-digit work order, **8041** | Players immediately see a four-digit cash-box dial and may try the most obvious four-digit number | ~1 min | Footer says **“FACILITIES — NOT A VAULT RECORD.”** Every genuine puzzle document carries “VAULT OPERATIONS.” | | **Old Exchange-Rate Sheet** | Dense table of currencies and numbers posted among bank paperwork | Looks computational and attracts spreadsheet/engineering instincts | ~2–3 min | Large header says **“CUSTOMER LOBBY REFERENCE — EXPIRED.”** None of the puzzle instructions ever references currency or exchange. | | **Box 13 Closure Notice** | Official-looking notice mentioning “Deposit Box 13 — contents removed” | Fits the secret-deposit-box story almost perfectly | ~1–2 min | It is stamped **“CLOSED / INVENTORIED / NO EXCEPTION”** three times. The premise asks specifically for an *unlisted* box. | Total likely red-herring tax is therefore modest: approximately 2–5 minutes rather than enough to derail inexperienced players. --- # 5. TIERED HINT SCRIPT Volunteer timings are **wall-clock thresholds**, not “minutes spent on puzzle.” If the team has already advanced, skip obsolete hints. ### Puzzle 1 — Closing Balance **Tier 1 — minute 3:** “The vault officer trusted balanced books more than hidden messages. Which book in this room still needs closing?” **Tier 2 — minute 5:** “Audit the ledger. Every row claims that its deposit and interest produce its closing balance.” **Tier 3 — minute 7:** “Check each row's addition. Three rows do not balance. Take the final digit of those three transaction IDs from top to bottom.” **Tier 4 — minute 9:** “The failed rows give **317**. Put **317** into the first padlock.” ### Puzzle 2 — Invisible Ink Department **Tier 1 — minute 9:** “Some bank records were designed to look clean under ordinary office light.” **Tier 2 — minute 11:** “The audit packet is telling you to use the UV torch on documents already in the room.” **Tier 3 — minute 13:** “Find the three UV number words beside approval stamps 1, 2 and 3. Read them in stamp order.” **Tier 4 — minute 15:** “The hidden numbers are six, four, two: **642**. Open the second padlock.” ### Puzzle 3 — Exception Account **Tier 1 — minute 16:** “An exception survives every control, not merely most of them.” **Tier 2 — minute 19:** “Treat the six accounts as candidates in a logic elimination puzzle. Cross out any account contradicted by even one rule.” **Tier 3 — minute 23:** “Start with the dates: remove Monday and Friday. Then require evening access and a high balance. Use the officer rules to resolve what remains.” **Tier 4 — minute 27:** “The only account satisfying every restriction is **5831**. Turn that account card over.” ### Puzzle 4 — Four Eyes Authorization **Tier 1 — minute 27:** “The bank cared about who signed—but also who had seniority.” **Tier 2 — minute 30:** “Sort the four authorization slips by officer tenure, greatest to least.” **Tier 3 — minute 33:** “Arrange the slips 12 years, 9 years, 6 years, then 2 years. Put their marked edges together and read the joined lettering.” **Tier 4 — minute 36:** “The assembled message is **NORTH WALL**. Go to the document there.” ### Puzzle 5 — After-Hours Recording **Tier 1 — minute 34:** “The security system recorded plenty of activity. The vault cared only about activity after the customers were gone.” **Tier 2 — minute 37:** “Compare every timestamp in the recording with the bank's 18:00 closing time.” **Tier 3 — minute 40:** “Ignore the 17:42 and 17:55 calls. Write down the inspection code from each call after 18:00, in chronological order.” **Tier 4 — minute 42:** “The four after-hours codes are 4, 9, 2, 6: **4926**.” ### Puzzle 6 — Final Reconciliation **Tier 1 — minute 43:** “Nothing new needs to be discovered. The bank wants its authenticated records reconciled.” **Tier 2 — minute 47:** “The Final Audit Sheet tells you which digit to extract from each answer you have already proved.” **Tier 3 — minute 51:** “Take digit 1 of 5831; digit 2 of 642; digit 3 of 4926; and digit 3 of 317. Enter those four extracted digits in that order.” **Tier 4 — minute 55:** “The final deposit-box combination is **5427**.” At minute **58**, regardless of progress, jump directly to whatever Tier 4 is necessary to ensure the group reaches the physical cash-box opening before the hard cap. --- # 6. TIME CALIBRATION TABLE | Puzzle | Fast group | Target | Slow group | Cut or simplify option | | ------------------------ | ---------: | ---------: | ---------: | -------------------------------------------------------------------------- | | Closing Balance | 2 min | 4 min | 7 min | Circle the six rows worth checking instead of requiring a full-ledger scan | | Invisible Ink Department | 3 min | 6 min | 8 min | Print “UV” subtly on the Night Audit Packet | | Exception Account | 6 min | 10 min | 15 min | Remove two decoy accounts and one redundant constraint | | Four Eyes Authorization | 5 min | 8 min | 12 min | Print tenure directly in large type on each fragment | | After-Hours Recording | 4 min | 7 min | 10 min | Provide the audio transcript alongside playback | | Final Reconciliation | 6 min | 10 min | 13 min | Pre-fill the four previous answer strings on the Final Audit Sheet | | **Total** | **26 min** | **45 min** | **65 min** | GM hints should hold slow groups below the 60-minute cap | To retune the experience: * **Subtract ~15 minutes:** Use the four-account version of **Exception Account** (about −5), provide a transcript for **After-Hours Recording** (about −3), print tenure prominently on **Four Eyes Authorization** (about −3), and pre-fill the prior answers on **Final Reconciliation** (about −4). * **Add ~15 minutes:** Expand **Exception Account** from six to eight accounts with two additional valid elimination rules (+5), make **Four Eyes Authorization** six fragments instead of four (+4), and require players to transcribe all six audio calls onto a blank security log before filtering them (+6). Do not add red herrings to manufacture difficulty. * **For a group running unexpectedly fast or slow:** Preserve Puzzles 1, 3 and 6—the confidence builder, difficulty peak and finale. Tune Puzzles 2, 4 and 5 instead. This maintains the intended difficulty curve rather than making the ending arbitrarily harder. --- # 7. BUILD SHEET ## Props and materials by puzzle ### Shared room dressing Using the available printed-document allowance, prepare: * “VAULT 3B — FINAL NIGHT” entry notice * “Vault Operations” header/footer template for all genuine documents * “Public Branch Hours — Closing 18:00” notice * Staff Authorization Register * Three red-herring documents * Whiteboard with “EXCEPTIONS MUST SATISFY **ALL** CONTROLS” * Whiteboard markers * UV torch * Bluetooth speaker * Two 3-digit combination padlocks, set to **317** and **642** * 4-digit cash box, set to **5427** No phone, internet access, calculator, outside trivia, or player-owned object is required. ### Puzzle 1 — Closing Balance Print one Final Teller Ledger with approximately 10–12 rows. Each row contains: `Transaction ID | Deposit | Interest | Closing Balance` Make exactly three equations false. Their transaction IDs must end, top-to-bottom, in **3**, **1**, **7**. Padlock A secures the Night Audit Packet. If there is nothing in the conference room suitable for physically chaining a packet shut, punch two holes through the folded packet and pass the padlock through both holes. ### Puzzle 2 — Invisible Ink Department Prepare: * Night Audit Packet * UV torch * Three ordinary-looking Vault Operations documents * UV markings **SIX**, **FOUR**, **TWO** * Visible approval stamps numbered 1, 2, 3 * Padlock B set to **642** For robustness, test the UV markings under the actual conference-room lighting before play. They should be invisible or genuinely difficult to notice without the torch but immediately legible with it. Padlock B similarly passes through holes in the folded Exception File. ### Puzzle 3 — Exception Account Prepare: * Exception File * Six account cards containing the exact table data above * Five printed restriction statements * Reverse of **5831** containing the Four Eyes instruction * Reverse of every other card printed “STANDARD ACCOUNT” Give players enough blank whiteboard space to make elimination marks. Do **not** require them to know how a formal logic-grid diagram works. ### Puzzle 4 — Four Eyes Authorization Prepare four heavy-paper slips. Each contains: * Officer name * Tenure: 12, 9, 6 or 2 years * One quarter of the assembled message * Registration marks showing how the pieces physically align When ordered 12→9→6→2, the fragments must visually produce **NORTH WALL**. Because conference rooms do not reliably have an obvious north wall, do not depend on actual compass knowledge. Put a small printed architectural orientation marker reading **NORTH** on the appropriate side of the whiteboard from the beginning. “NORTH WALL” therefore means “the wall identified as NORTH inside this room.” ### Puzzle 5 — After-Hours Recording Prepare: * Bluetooth speaker * Preloaded/local recording of the six-line security script * Printed Security Call Log * Printed closing time of 18:00 * Four extraction boxes * Final Audit Sheet concealed by the **4926** extraction A simple implementation avoids introducing another physical container: number twelve narrow columns across the Security Call Log. Columns **4, 9, 2, 6**, read in that order, contain vertically aligned fragments spelling “TURN OVER.” The reverse is the Final Audit Sheet. This makes **4926** operational rather than merely another answer to remember. ### Puzzle 6 — Final Reconciliation The Final Audit Sheet reads: > **VAULT 3B — FINAL RECONCILIATION** > Only authenticated records may authorize closure. > > Exception Account **5831** — take digit **1** > Night Audit **642** — take digit **2** > Security Record **4926** — take digit **3** > Closing Balance **317** — take digit **3** > > ENTER: □ □ □ □ Extraction: * **5831**, digit 1 → 5 * **642**, digit 2 → 4 * **4926**, digit 3 → 2 * **317**, digit 3 → 7 Final combination: **5427**. Inside the cash box place a printed certificate: > **VAULT 3B — CLOSED ACCOUNT** > UNLISTED DEPOSIT RECOVERED > FINAL AUTHORIZATION ACCEPTED > > The bank may forget. The ledger does not. ## Reset checklist 1. Remove the closing certificate from wherever the winning team left it and return it to the cash box. 2. Scramble and close the cash-box dial; verify its combination remains **5427**. 3. Return the Final Audit Sheet to the reverse/concealed position of the Security Call Log. 4. Reset the Bluetooth audio to the beginning and verify the speaker is charged and paired to the GM device. 5. Return the Security Call Log to **NORTH WALL**. 6. Separate and randomize the four Four Eyes Authorization slips. 7. Return all six account cards to the Exception File with **5831** face-up like the others so its reverse is hidden. 8. Close the Exception File with Padlock B and scramble it; verify **642** opens it. 9. Return all three UV-marked documents to their starting positions. 10. Return the UV torch to its visible starting position and verify its battery. 11. Close the Night Audit Packet with Padlock A and scramble it; verify **317** opens it. 12. Restore the Final Teller Ledger. 13. Erase all player writing from the whiteboard except the permanent/setup text. 14. Restore the NORTH orientation marker, branch-hours notice and Staff Authorization Register. 15. Restore all three red herrings. 16. Perform a complete lock test in progression: **317 → 642 → 5831 → NORTH WALL → 4926 → 5427**. 17. Scramble every lock again before admitting the next group. ## Two likely game-breaking failure modes **1. Players discover later-stage documents early.** A conference room provides limited true concealment, so an aggressive eight-person search team can encounter the Security Call Log or account materials out of sequence. **Fix:** Design information gating rather than relying on hiding. Later documents may be physically visible, but they must be uninterpretable without the preceding instruction. Label genuine paperwork by department rather than “Puzzle 5,” and ensure **NORTH WALL**, **5831**, and **4926** only acquire actionable meaning after their respective upstream solves. The two locked packets provide the only hard gates necessary. **2. Eight players create a bottleneck around one sheet or one audio source.** With a large competitive group, a puzzle that can only be inspected by two people leaves six people disengaged and encourages premature lock-spinning. **Fix:** Print account cards and authorization fragments as separate objects that can be distributed. For the audio puzzle, play the recording loudly enough for the whole room and allow unlimited replay. During Puzzle 3, explicitly make the six account cards separable so several players can independently test constraints while one person records eliminations on the whiteboard. This turns the group's size into an advantage without making parallel solutions necessary for correctness. **Total estimated solve time for the target group: 45 minutes.**