Continuing 0one's development of quality play-aids, in this product they supply a DM map of a location, nine customisable tiles depicting that location suitable for miniatures use... and suggestions as to what might be going on in that location. The location is an underground lair used by a medusa located near a city. In the notes, you'll find out about the medusa and how she operates, sufficient background to enable you to put together suitable rumours and other hooks to get the characters involved.
The map and associated tiles detail the medusa's entire lair, while the notes give a brief description of each room and what might be happening there. As usual with an 0one product, you can exert quite a lot of control over the maps; turning the grid on or off, choosing whether or not it is furnished and so on. As the series name suggests, the maps are black & white line art, all neatly done.
For a quick adventure, you'll only need to check the monster and NPC stats, add some treasure and you are ready for the characters to arrive. A proofread by an English speaker would improve the notes, otherwise there is nothing to fault!