The official investigation rule
Store copy is blunt: optional cases never gate the campaign. You can finish Calvin’s rescue stake without closing every board. The same sentence says those cases still pay — safer routes through flooded streets, hard supplies you will not find by charging every fight, and upgrades that sit behind the Investigation tab rather than behind a paywall. That is why this file lives next to Survive Arkham instead of under a walkthrough URL.
The Investigation HUD tab is the evidence graph. The official still shows Area Progress, linked testimonies, and digit memos. It does not show a complete case list for the whole city, so the table below only repeats achievement titles and the nodes visible on that one screenshot. If a video claims a hospital-second-floor code or a demo safe combination, that string is not on Frogwares’ store or news posts captured for launch, and it is not reprinted here. Safer routes and hard supplies are the official payout language: treat an optional board as a logistics job, then return to the main rescue stake when the graph stops paying.
Eight Investigate… titles
Public Steam descriptions are one line each. The Inheritance: investigate the wall safe. The Other Gods: investigate the church mystery. The Siren’s Call: investigate the alluring song. The Red Press: investigate the cursed press. The Whisperers: investigate the machine connected to the brains. The Vault: investigate the locked storage. The Drowned: investigate the mysterious locker. The Damned: investigate the sixteen punishments. Those eight strings are the entire first-party case roster with names. None of those lines name a district slug or a numeric combination, which is why this table stops at the official hint and refuses to pad a walkthrough.
Hidden achievements such as Welcome To Arkham! and Soulmates are not given public Investigate… text on the community page, so they are not treated as optional-case titles here. Mycophile, Behind Every Crate Man..., What Dreams Are Made Of, and For Her are collection or meta achievements, not case names. Filter the full 23 on Steam Achievements if you need the hidden flag.
| Case | Official hint |
|---|---|
| The Inheritance | Investigate the wall safe. |
| The Other Gods | Investigate the church mystery. |
| The Siren's Call | Investigate the alluring song. |
| The Red Press | Investigate the cursed press. |
| The Whisperers | Investigate the machine connected to the brains. |
| The Vault | Investigate the locked storage. |
| The Drowned | Investigate the mysterious locker. |
| The Damned | Investigate the sixteen punishments. |
What the official board actually shows
The launch-gallery still of the board is a UI document, not a fan mockup. Visible nodes include Testimony of Cornelius Wright, Testimony of Ambrose Pence, Testimony of Silas Dunwich, Note (Wireless Room), Occult Symbol, Prism System Plans, Letter with Digit, and Memo with Digit. Area Progress reads 19/19 on that capture. Those names are why this page exists: so you can recognize the board in your own HUD without copying a competitor’s spoiler graph. Wireless Room and Prism System Plans are UI labels, not invented room slugs for a /walkthrough/ tree.
Cornelius, Ambrose, and Silas are testimony labels, not character slugs. This site does not create /characters/ URLs for them. Digit memos confirm that some cases use numeric clues; they do not publish the digits. Pair the board with the Survive Arkham loop: if a case is paying in shortcuts and shells, it is doing the job the store described. Terms such as Codex and Talent that appear around the same HUD are defined on Arkham Glossary.
- Testimony of Cornelius Wright
- Testimony of Ambrose Pence
- Testimony of Silas Dunwich
- Note (Wireless Room)
- Occult Symbol
- Prism System Plans
- Letter with Digit
- Memo with Digit
Using the board without a spoiler atlas
Play the Investigation tab as a ledger. When Area Progress is incomplete, the official still implies you still have nodes to pin — testimonies, a wireless note, an occult symbol, prism plans, or a digit memo. When it reads 19/19 on that capture, that particular board is finished. The store does not say every district uses a 19-node graph, so do not treat 19 as a city-wide quota for every flooded street.
Optional cases sit beside the six HUD tabs, not instead of them. Inventory and Crafting still decide whether you can spend the supplies a case unlocked. Talents still spend Dream Essence from the Field Kit. Map still shows the Anatomical Theater objective in General Ward. The board is one tool in that set. If you came from a competitor walkthrough that lists hospital-second-floor codes, those strings are not first-party and are not mirrored here. Use the eight Investigate titles in the table as names only.
What this roster refuses to invent
A complete optional-case walkthrough would need district slugs, numeric combinations, and a spoiler graph of every testimony. Steam’s public achievement HTML gives eight Investigate… one-liners and nothing else. The official board still gives nine visible node labels and a 19/19 Area Progress stamp. That is the entire first-party case atlas at capture. Hidden achievements such as Welcome To Arkham! and Soulmates stay on the achievement filter; they are not extra Investigate titles.
The payout language is specific: safer routes, hard supplies, upgrades. It does not promise extra story chapters, a second campaign, or a complete Oakmont leftover map. Charles Reed and Oakmont belong to The Sinking City Remastered on the same Steam news hub. If you need prices for the Field Kit that teaches a Talent early, use Editions and Kits. If you need the 18 August 2026 window, use Release and Platforms.