From publisher blurb:
In the ancient village of Coralius, built in the ruins of a lost empire, there has always been the Horn. Many have studied it, many have theorized about it, but no one has ever discovered its secrets. Recently in the night the horn has begun to glow and the apprentices of the Mage Academy have gone missing.
Can the adventurers discover what happened to the apprentice mages and the secret of the Horn?
Under the Horn is a 2-page adventure for players between 1st and 3rd level. The adventure was developed for use with Frog God Game's Swords & Wizardry but can be easily converted to nearly all OSR style retro-clones and rule sets.