The Carstairs Incident

From the introduction:

Carstairs, Alberta is a tiny town - population around 3500, occupying less than 12 square kilometers. Normally, it’s a sleepy place, a town that more people pass through than stop in, as it lies 48 km north of the busy city of Calgary. It’s the kind of town where everyone knows each other, and there are no secrets.

Or so people believe. A terrible secret is soon to be unveiled, and Carstairs just may become the epicenter of the apocalypse.

User summary:

This item includes a brief introductory scenario, quick start rules, pre-generated characters, and several pages of print-and-play components.