The Sign of the Four

Mary Morstan brings Sherlock Holmes a puzzle with no crime attached: ten years ago her father vanished; for the last six, someone has anonymously sent her a flawless pearl every year; and now that someone requests a meeting. From this delicate opening Doyle unspools his second Holmes novel into a story of a locked-room death, a stolen Indian treasure, a pact made in a colonial fortress, and a pursuit that ends in a full-throttle steam-launch chase down the Thames at night, the most cinematic sequence in the canon.

This is also the book where Watson, tagging along, finds himself paying rather more attention to the client than to the case. Vintage Holmes at his sharpest and strangest, in a mystery that spans decades and continents yet resolves with perfect precision.

At roughly 43,500 words, The Sign of the Four runs about 5 hours at 1x narration speed. That figure is an estimate based on a typical narration pace. The exact length depends on the voice and the playback speed you choose.

The Sign of the Four is in the public domain, so the complete text is free on Project Gutenberg and LoudReader has the entire Project Gutenberg catalog built in. To listen:

1. Download LoudReader for Mac or iPhone (free, no account).
2. Search for “The Sign of the Four” in the built-in catalog and add it to your library.
3. Press play. A natural offline voice reads the book while each word highlights on screen, and your place is saved between sessions.

LoudReader reads with natural offline voices, so the whole book works on a plane or underground. It is fully on-device and private, your library never leaves your device. Listening is unlimited on the free tier.