There's something odd going on in a local dormant volcano. For a start, any flame bends to point towards it. If that sounds odd to you, maybe it's time to investigate...
The DM is provided with an adventure summary - it's a fire-themed delve - as well as encounter tables, scaling information and a more detailed backstory to explain just what's going on down there. There are also some quite innovative adventure hooks to get the party interested - for example, during an earlier adventure, someone casting a fire-based spell gets an irresistable urge to go visit the volcano in question. It's worth noting that the volcano is no longer completely dormant, and it's hot in there. Party members in heavy clothing or armour are going to suffer, and everyone needs to keep well hydrated. There's boiling water and magna to contend with as well.
As usual, the adventure proper begins with the party on the threshold: in this case, standing outside a cave in the volcano. It won't be long before they meet some of the strange inabitants, including a new race called klaklin, lobster-like humanoids who seem immune to heat. Anyone who enjoys exotic wildlife will have a field day here, there are plenty of strange creatures to study... if they don't try to eat you first. With the remnants left behind by previous inhabitants and new arrivals there is a lot to do, see and fight... and even a talking sword which has some useful background information (a neat and novel way to share the backstory with the party).
There's quite a lot going on down there under the mountain, yet when the party returns to the outside world everything seems just as it was. Will anyone believe their tales and recognise them for the heroes that they are? There are some good ideas for follow-up adventures based on some of the encounters. There are new races and monsters, a couple of magic items, and even four 8th-level pregenerated characters if you want to jump right in (well, you would benefit from transcribing them onto character sheets) as well as handouts and illustrations galore. A thoroughly enjoyable and origninal delve.