Clues & Culprits › Archive › Oct 16, 2026 Hard walkthrough
Oct 16, 2026 Full Proof Walkthrough
Every verdict in the Hard case “The Grey Lady of Staircase Nine”, in an order where each step is proven by the statements already on file.
Play it first Just a hint, please
This Hard case seats 20 suspects on a 4×5 grid. 15 of them carry a clue; the other 5 only have something to say about themselves. 6 of the steps can only be proven by reading two or more clues together. The order below is one valid route; any order where each verdict is proven when you enter it reaches the same answer.
Spoiler: show the full walkthrough
Start: Ezra (A2) begins the case proven innocent.
The only campus nurse in Row 1 is a criminal.— Ezra, drama student (A2)
Step 1: Dina (D1, campus nurse) is a criminal. This follows from Ezra’s statement and the verdicts already proven.
Step 2: Tess (D5, undergraduate) is a criminal. This follows from Dina’s statement and the verdicts already proven.
Tess and I share the same verdict: both criminal or both innocent.— Dina, campus nurse (D1)
Step 3: Petra (D4, undergraduate) is a criminal. This follows from Tess’s statement and the verdicts already proven.
Otto and I have no innocent neighbors in common.— Tess, undergraduate (D5)
Step 4: Sadie (C5, college porter) is a criminal. This follows from Tess’s statement and the verdicts already proven.
Step 5: Mila (A4, drama student) is innocent. This needs 2 statements together — Petra’s and Sadie’s. Assume the opposite verdict and at least one of them breaks.
Exactly six of the fourteen people on the edges are criminals.— Petra, undergraduate (D4)
Row 1 has more criminals than Row 4.— Sadie, college porter (C5)
Step 6: Leo (D3, undergraduate) is innocent. This needs 3 statements together — Petra’s, Sadie’s and Mila’s. Assume the opposite verdict and at least one of them breaks.
If Leo is a criminal, then so is Ruby.— Mila, drama student (A4)
Step 7: Otto (C4, groundskeeper) is innocent. This needs 3 statements together — Petra’s, Sadie’s and Leo’s. Assume the opposite verdict and at least one of them breaks.
If Otto is a criminal, then so is Ruby.— Leo, undergraduate (D3)
Step 8: Hattie (D2, campus nurse) is innocent. This needs 3 statements together — Petra’s, Sadie’s and Otto’s. Assume the opposite verdict and at least one of them breaks.
Exactly two of Ruby's five neighbors are criminals.— Otto, groundskeeper (C4)
Step 9: Gemma (C2, college porter) is innocent. This follows from Hattie’s statement and the verdicts already proven.
The person between me and Frank is innocent.— Hattie, campus nurse (D2)
Step 10: Ivan (A3, groundskeeper) is innocent. This needs 3 statements together — Petra’s, Sadie’s and Otto’s. Assume the opposite verdict and at least one of them breaks.
Step 11: Frank (B2, campus guard) is a criminal. This follows from Ivan’s statement and the verdicts already proven.
If Frank is innocent, then I'm a criminal.— Ivan, groundskeeper (A3)
Step 12: Bea (B1, college porter) is innocent. This follows from Frank’s statement and the verdicts already proven.
Cora and I have no criminal neighbors in common.— Frank, campus guard (B2)
Step 13: Kira (C3, drama student) is innocent. This follows from Gemma’s statement and the verdicts already proven.
Jasper and I have exactly one criminal neighbor in common.— Gemma, college porter (C2)
Step 14: Cora (C1, drama student) is a criminal. This needs 3 statements together — Sadie’s, Otto’s and Kira’s. Assume the opposite verdict and at least one of them breaks.
Exactly one of the four people in the corners is innocent.— Kira, drama student (C3)
Step 15: Nora (B4, campus guard) is innocent. This follows from Cora’s statement and the verdicts already proven.
Row 4 has exactly three innocents.— Cora, drama student (C1)
Step 16: Quentin (A5, college porter) is a criminal. This follows from Otto’s statement and the verdicts already proven.
Step 17: Arlo (A1, undergraduate) is innocent. This follows from Petra’s statement and the verdicts already proven.
Step 18: Ruby (B5, campus guard) is innocent. This follows from Petra’s statement and the verdicts already proven.
Step 19: Jasper (B3, groundskeeper) is a criminal. This follows from Bea’s statement and the verdicts already proven.
There are exactly two criminals below me.— Bea, college porter (B1)
The final lineup
| A | B | C | D | |
|---|---|---|---|---|
| 1 | Arlo innocent | Bea innocent | Cora criminal | Dina criminal |
| 2 | Ezra innocent | Frank criminal | Gemma innocent | Hattie innocent |
| 3 | Ivan innocent | Jasper criminal | Kira innocent | Leo innocent |
| 4 | Mila innocent | Nora innocent | Otto innocent | Petra criminal |
| 5 | Quentin criminal | Ruby innocent | Sadie criminal | Tess criminal |
What happened
Staircase Nine was let to tourists by the night at £300 a room. Quentin and Sadie, the porters who held its keys, ran the bookings from the lodge; Cora, a drama student with a gift for melancholy, played the grey lady in a borrowed nightgown and a cloud of talcum powder until every student had moved out. Frank, the campus guard, reported creaking beams so the college sealed the staircase, and Jasper, the groundskeeper, carried the guests' luggage up the back way. Petra and Tess, two undergraduates, cleaned the rooms between bookings, and Dina, the campus nurse, supplied fresh sheets from the sick bay.