With the title 'Bad Light' given to a scenario set on an ocean coastline near a trade route that's threatened by a reef, and a plot which centres around a light-tower built against a cliff it's quite easy to guess what might be going on... but there's a bit more to it, as the adventure background lays out for the DM. Moreover, there is more than one way for the party to solve the problem, which gives a nice feeling of freedom of action and allows for ingenious ideas and tactics,
Several hooks are provided to get the party involved, neatly giving a variety of options so that you can spring this on them pretty well whatever they think they are doing at the time. However, it's primarily a site-based adventure, with the action proper beginning once they arrive at the lighthouse, which rejoices in the name of the Pearl Tower having once been coated in mother-of-pearl scales (long gone now, pinched by raiders). A plan is provided, along with detailed descriptions of who and what is to be found there.
There's also a secondary location that needs to be visited, covered in less detail so you may want to spend some time on designing the surroundings. Once matters have been dealt with - and that will require fighting, the antagonists are not the sort to be talked out of their activities - there's a brief mention of some follow-up activities. Overall it's a neat little adventure that can be dropped in somewhere suitable as part of the exploits of a typical band of adventurers.