The city of Porthaven has grown and prospered over the past three hundred years, with a reputation for being peaceful, a safe harbour from storms and with a temperate climate. It wasn't always like that... the place where it was built was originally unstable both geologically and meterologically (perhaps not the best place to found a settlement?), and the way in which it reached its present serenity has been lost over the years to all but a few... and they don't really understatnd it.

The DM's backstory explains all, and as soon as a bunch of high-level adventurers like the party turns up they will be shown the mysterious 'machine' built by a traveller through the planes called Khyber Mercane and some creatures called modrons - noted for a love of order matched only by a thirst for knowledge - that he encountered in his travels. For a while, modrons came each year to service the machine, but they have not been back for a long time and, according to the leading priestess of Wee Jas - who has been studying ancient texts in an attempt to find out what's wrong - it has run out of fuel. So trips to the four elemental planes are required to obtain what the machine needs.

Some hooks are provided to help you get the party to Porthaven, once there they find that there is a massive storm raging and then a nearby volcano erupts... amidst the chaos the party will be shown the machine and the priestess explains what she has discovered so far. The rest of the adventure consists of visits to the elemental planes with brawls with the inhabitants and occasional chances to talk to a few of them as the party collects the material that they need.

It is a fairly straightforward adventure which may be a bit simple for parties accustomed to planar travel - and perhaps a bit hard for those who have never attempted it before. There are a couple of vague ideas for follow-on adventures, and a neat new monster which is encountered for the first time on one of the planes, and that's it.