The Sunken City is our first-party ocean-horror ARG: an anonymous email about counting lights off Lan City leads journalist Shen Yu to a thirty-century fishing port, and to a city fifty metres under the sea. 8 acts, 15 puzzles, 20 simulated websites, 36 collectible clues, 4 endings, 5–8 hours.
July 2026. Freelance investigative journalist Shen Yu gets an anonymous email: strange lights off Lan City — not boats, not buoys; they have patterns, they are counting. Fifty metres down there is a city that does not belong to humanity. 8 acts, 15 puzzles, 20 simulated websites, 36 collectible clues, 22 emails, 4 endings, an 8-page lighthouse log, about 5–8 hours.
July 2026. Freelance investigative journalist Shen Yu receives an anonymous email: “Strange lights have appeared in the waters off Lan City. Not fishing boats. Not buoys. They have patterns. They are counting.” Three days later she reaches this small town on the south-eastern coast.
Lan City has three thousand years of fishing history, three hundred years of tidal songs, and one legend nobody has ever confirmed: fifty metres under the sea there is a city that does not belong to humanity. Fishermen call it the Underwater Palace; marine scientists call it a geological anomaly. But everyone who watches the water at midnight agrees: those lights are looking up from below.
It is played as a pseudo-interface investigation: the whole game is a browser, and you hop between twenty simulated websites — the fishing lodge, the tide forum, the evening news, the marine institute, lighthouse logs, the folk museum, the digital rare-book archive, catch reports, the harbour bureau, government releases, the hospital, deep-observer field notes, social snapshots, tide telemetry, geological survey, police notices, the Dark Water archive, church records.
The dread is not jump scares. It comes from assembling unrelated public records into one conclusion: a 222-year cycle, and a door that is being opened.
The four are decided by the choice in puzzle 12, and two of them also depend on how many clues you collected; exact triggers are listed in the walkthrough.
With all eight lighthouse pages, every ending gains a page headed “tonight’s keeper.” It changes no branch; it is their shared coda.
Chen Shoudeng kept the Wanghai light for forty years. Beyond the official log he kept his own copy: from the page his father handed him in 1960 to the last page he wrote on 18 June 2026.
The log unseals with the acts, one page per act. Each page records the date, the sound he heard that night, what happened, and one line he left at the bottom — not a conclusion, but a sentence still waiting for an answer.
The entrance is at the top of the evidence panel: “Wanghai Lighthouse log n/8.” All eight are guaranteed before the final chapter; with the full set, every ending gains a page called “tonight’s keeper,” reading from 1960 to tonight, with the last line left for Shen Yu.
The log gives no puzzle answers. It fills in what this town heard, on the lit side of the water, across seventy years.
The eight object photographs are AI-generated illustrations used to fill in the objects, not screenshots of the game.
It is the longest game here: 5–8 hours, twenty sites, thirty-six clues. It does not try to frighten you in one sitting; it lets you finish a fictional city's public record the way an investigation actually ends.
The puzzle types are the most varied on the site: text input, redaction recovery, Morse, spectrogram tuning, sequence verification and date arithmetic each take a stretch, so no single trick repeats fifteen times.
All four endings are fully written, not one scene recoloured: sealing, answering, entering and singing are four postures towards the same door.
If you play only one of our ARGs, this is the biggest one. If you prefer to start short, begin with Unclaimed or Last Online.
Lan City is shared geography: the sonic experiments of Tide Sound Archives, the abandoned asylum of Eye of the Abyss and the polluted town of Rust River all sit on the same map.
This is the game that takes the sea all the way down: the tidal cycle, the seabed structure and the song-memory are the settings the others keep citing.
No required order. Play this first and the others fill in details; play the others first and several coordinates here will look familiar.
Eight acts come from the entries in acts.js, fifteen puzzles from puzzles.js, twenty simulated sites from locations.js, twenty-two emails from emails.js, and four endings plus one epilogue from endings.js.
Thirty-six is the denominator the evidence bar itself uses (the size of the collectible clue set in App.vue), not the row count of the clue data file — that file holds entries that are not collectible. The 5–8 hours is the game's own stated playtime.
The eight lighthouse pages, their dates, keepers and sounds come from lighthouse.js; the build gate checks one page per act, all eight images, and has negative controls (a duplicate act or a missing image turns it red).
Both screenshots were taken from the running game on 2026-10-19. The hero image is an AI-generated illustration, not a game screenshot, labelled at the top of the page. If a number here disagrees with the game, the game is right; tell us in the changelog.
For players happy to spend several evenings reading a fictional coastal city's public record and matching dates against frequencies.
Not for players wanting something short and sharp — reading twenty sites takes time — and not for anyone who cannot take ocean horror at all.
Do I need an account or payment?
No. It runs in the browser, free, with no account or in-app purchases.
Must I play the other universe entries first?
No. What is shared is geography and underlying settings; each game's main line closes on its own.
How long is it?
About 5–8 hours; seeing all four endings takes longer, and two of them depend on clue count.
Where is progress saved?
Locally in the browser. Refresh or close and continue; it does not sync across devices, and clearing site data restarts.
What if I am stuck?
Check the evidence bar and the keyword chips, then search again; every answer is in the body text of an unlocked site — no outside sources needed.
Can I switch to English?
Yes; both the interface and the site content have English versions.
Can I miss the lighthouse log?
No. It unseals one page per act and is complete before the final chapter; the full set adds a “tonight’s keeper” page after every ending.
What if it will not open?
Try a current Chrome, Edge or Firefox. If it still fails, email contact@gamestrategists.com with your device and browser version.
Start investigation — Runs on its own subdomain · progress saved locally · Chinese and English