Designed as a promotional piece, this adventure runs in a single session and involves the investigation of a mysterious tower that just suddenly appears in the middle of a forest, the red light on its top echoing a hitherto-unknown comet that has appeared in the sky.
The backstory is ingenious and provides a perfectly plausible reason for the tower's appearance, a tale you'll be dying to share with your players. The first their characters will know that anything is afoot is when a 'bearded star' is spotted in the sky, assumed by astronomers to be a comet. It's a whitish-green shade and the tail is a bit wiggley, so it is called Serbok, an archaic word meaning serpent. Scarcely have the rumour-mongers started in on the usual predictions of misfortune that accompany the sighting of a comet than folk in a nearby wood announce that a large lake with a strange tower beside it has suddenly appeared there. The tower looks like it has a hide of dark scaly leather and a red light shines from its top. If the party does not rush off to investigate immediately, have local law enforcement hire them to take a look.
The adventure proper begins with the party arriving at the edge of the forest and making their way through it to the tower. Once they venture inside, it is weird and strange indeed... yet all makes an odd kind of sense once you know the thing's true origins. The Big Bad at the end might, just might, be persuaded to explain what he's up to; but is more inclined to attempt to polish off these pesky intruders, or die trying.
Tower conquered, the party steps out... only to be greeted with an amazing sight. This is left hanging, with a vague promise that it might form a subsequent adventure - or the Judge may making something up. It's a fun adventure, with some seriously weird features, but the ending is unsatisfactory with no clear closure. Perhaps you'd better make something up to provide a proper end to the adventure!