You can buy it at DrivethruRPG for USD $1.00 HERE (aff).
Included in this PDF is a broad-strokes setting. The adventure takes place on Valsuum, a world on its downfall. Once the center of a great empire with access to wealth and knowledge, it now houses three races who fight about the resources of this barren planet.
The author provides stats for the rat-like Bromans while Humans follow the rules of the White Star rulebook and Tars use the "Alien Brute" class template from WS.
Bromans are intelligent creatures who build underground cities and are known as excellent tradesmen and merchants. They are agile and nimble and are proficient with missile weapons. Tars are enormous big four-armed reptilian aliens. They are nomads and salvage technology from ruined cities.
Valsuum is on the decline and while firearms are still common, advanced technology is not available anymore. However, there are ancient devices left, so there are still sky ships and star swords.
What's the adventure about?
Generally, it feels quite pulpy which fits White Star like a glove.
Warning: spoilers ahead!
The plot hook is the crash of a sky ship, including a damsel in distress who the players can save from a group of Black Guards. Yes, as a woman I cringe a bit but the idea is well within the realms of pulp literature.
The spacecraft contains a mysterious note and a hint to the ancient ruins in the East, the so so-called Pillar of Air and Water.
The players have the choice to visit a Broman Outpost to nurture to woman back to life and can find out more about her and her story.
The adventure includes a random encounter table which has a 4 in 6 chance of trouble.
On the way to the Pillar of Air and Water the players will also come across an ancient city which is occupied by Tars and also violent Giant Apes. The players will need trickery or diplomacy to make it through.
The main part of the adventure takes place in the Pillar itself. The author included a map for this 7-room-mini-dungeon. The idea of the dungeon is very nice: it's an ancient site with strange technology: pipes and steam and a security system which fires energy bolts. Also, there is quite a big revelation for the world outlook of the players. The players can fight aliens and save the day and possibly the world of Valsuum.
Look & Feel
The product is a 14-pages PDF. There is a cover illustration and a map. The layout is simplistic but good to read. The text is mostly held in black and white but the author chose to color the headings in red which lets you easily distinguish it from the main text. The prose is easy to read but suffers from some minor grammatical errors and oversights. For instance, the rat-like creatures are first called "Brumans" and later the outpost is a "Broman" Outpost. Still, it's well within the margin of self-published works and nothing really grave, especially considering the price.
All in all, this is a functional product and the cover illustration looks lovely.
The adventure is not completely versatile if you want to play White Star as it takes place on Valsuum and thus the players are stuck there for the moment. That being said, it's well written and has some nice ideas. I like the "plot" which has wide reaching consequences for the world. Furthermore, the Pillar of Air and Water is a neat dungeon which makes use of pulp sci-fi tropes. The encounters look adequately balanced for a party of 1st level adventurers. (There is one exception which can end deadly if the players insist on violence but that's ok for an old school adventure.)
I know that there are many people who are very critical or commercial adventures for even one buck because there are many good free adventures out there. However, I feel that Gods of Air and Water is definitely a worthy product for USD $1.00. The adventure is somewhat of a railroad but offsets that with the interesting premise and the intriguing setting. If you want something fresh and don't want to come up with your own adventure, this is definitely a possible way to mitigate your prep time.
Personally, I'm not sure if I'd run it because it assumes that you want to play on Valsuum and I'm much more interested in space opera. It's certainly possible to get the players off planet but after introducing the world I'm not sure if it makes much sense.
Please note: I received a free review copy of the PDF. This review is a "reading review", I haven't played the adventure.