First off: This is the corrected and most up to date edition (the first edition was riddled with typos, whereas this has far fewer. Here is a link to the comparison of the errata of the first vs 2nd edition https://boardgamegeek.com/thread/1910213/second-printing-comparison-vs-errata-v16/page/2).
From checking with publishers the best way to tell that it's second edition is by looking for the names of the writes on the front of the box, below "Design by Hal Eccles", which is what this edition has. Additonally having purchased it from Gameology and checking the contents I can confirm this is correct.
If you like choose your adventures, or murder mysteries, Sherlock Holmes, or just Lovecraft you're very likely going to love this game. You can try the first case "A Grain of Evil" free on boardgame geek website.