The Far Outpost

From publisher blurb:

Is a generic fantasy short adventure designed for a low-level adventuring party of around three or more players. It’s themed around a frontier outpost calling for help among a mysterious attack of unprecedented proportions and unknown repercussions. The players must dwell into the remains of the outpost and fight off against the invading forces, rescuing whatever they can. This adventure should be around 4-5 hours long, and it’s meant to be used either as one-shot or a sidequest to your main campaign.