Treachery's Reward is a d20 System scenario for 1st- to 3rd-level characters. Part of AEG's Adventure Keep line of short, cheap modules in half-sized format (4-1/4"x11"), it is intended to be run as a single session. From the back cover:

Tara Mura is an indistinct village near the coast. The peasants who live here work hard and do their best not to attract attention from outsiders and few even know the tiny village exists. The road bends near Tera Mura as the sun slowly sets. Despite its boring appearance, it may have a passable inn.

A chill breeze blows through the pass, a strange, restless howl upon the wind. The moon hovers fat and full in a sky too bright for a night such as this. Perhaps it would be best to find a safe place to spend the evening.

The dry snap of a twig echoes in the high rocks to one side of the road. Several figures in black masks appear from behind the rocks, wielding rough-hewn spears. They outnumber the PCs two to one.

Perhaps this won't be such a boring trip after all.