The second novel in the series, also known as “The Sign of Four”, is set a few years further on from the events in A Study in Scarlet. Holmes and Watson have lived together for a few years when a young woman comes to them with a mystery. Her late father disappeared years ago and now an unknown person sends her a pearl once a year, along with a strange note. The adventure then unfolds with Holmes having to solve a locked room murder, and unraveling a complex tale of treasure and alliance among criminals.
Just as A Study in Scarlet, this one holds up very well today. The style is engaging and the story moves quickly. However, just as with the previous novel, I found the very long “explanation flashback” to be excessively long and quite jarring. Still an enjoyable novel for the brief time it takes to read it.