Running a mystery adventure is one thing. Writing a mystery adventure is a whole another beast. Smog on the Water provides enough contents, great story, and an intriguing mystery that DMs can run. Featuring interesting adversaries & NPCs such as the Yugoloths, the kuo-toa, and a drow, this adventure provides challenging things that the player characters can face. Using the Cloudkill spell as a plot point is a smart way that's uncommonly done in adventures. The module also gives much information on how to deal with certain encounters, and even how to RP the NPCs, which is surely a welcome addition to any modules. I would also like to say that the art is nice and the layout is readable. Though there are some wordings, sentences, and terms (e.g. using PC as a term instead of characters, adventurers, or heroes) that can be revised.

I personally feel that there should be more background information that needs to be fleshed out regarding each the main NPCs intentions and some other unanswered questions, but the information given in the module should suffice.

Despite that, the adventure module seems to be a good one coming from a first time adventure writer. It would be nice to see an updated version, or even an expanded one. I'm sure this adventure can kick off a whole another adventure on its own.