From the back of the booklet:
Shots fired at a New York clinic. Dissolving futuristic guns. Lunatics with swords. A bizarre disease, not of this world - but as someone initiated into the truth about the universe, you know other worlds exist, and they're just a few steps and a secret gate away. In the service of the Sodality, guardian order of the manifold planes, it's time to go exploring, whatever it takes you to grand magical cities or desolate hells.