The world of Contagion is not a pleasant one... and this supplement contains tools to help you make it even less so. All is not as that last sentence seems, however. Here are additional spells, rituals and other material that you might wish to add into your game - and some vicious combat moves that any sane individual would shy away from employing - how about yanking on the ears of those with the large pointy ones that adorn the heads of many of the more fantastical denizens, for example?
We start off with a collection of feats. An interesting one allows the use of a familiar by spellcasters, another lets you enthrall an NPC by flashing a bit of leg or in some other way flirting with them (the effect being a bit like a charm person spell), and yet another covers the inscription of ritual circles.
Then come the vicious combat moves, of which the less said the better, and some new rituals to research and perform. There are some new creatures as well, most of whom you don't want to meet down a dark alley on a moonless night.
A collection of various additions to the system that are worth a look, you may wish to add some or all of them to your game.