This supplement begins with the assumption that the campaign area is a powder keg of characters, situations, politics, and what have you, and then the arriving player characters are the spark. This is exactly the right way to think about adventures, and the rest of the book does not disappoint one bit.
You have a secret tropical island, in the vein of Isle of Dread, packed up with weird plants and creatures, volcanic eruptions, elemental spirits and lords, elven ruins, former slaves, lizardmen, nereid freedom fighters, salamanders, obsidian giants, a moronic efreeti drug kingpin, a couple demons and minor gods running the show from behind the scenes, and a bunch of birds about to be buried in lava and going extinct, among many other things and complications. We get a short biography of each, along with things they want and don't want, which is all it takes to give them plenty to do with each other, with players, and a boatload of personality and flavor. It gets everything out of the number of pages that it has.
The book opens with an overview of each of the island's hexes, all of them with some three interesting things - ruins, villages, dungeon entrances, etc. - to look at and explore more closely. They all get more detail later, as do the factions and the characters and the setting history. It's all put down very well and it's easy to grab all the important things at a glance, then the rest if the player characters decide to go that way next.
The only thing missing is stats. I suspect it tries to be system-neutral, but lacking in even any guidelines hurts the document somewhat. I could have used something. But it's a small quibble - nothing an experienced DM can't handle on his own - so I'd still highly recommend this to everyone as one of the best hexcrawls out there.