From the back cover:
ESCAPE THE CHASM OR DIE!
Death is on your heels, seekers! Whilst delving the awesome depths of a fantastic dungeon complex, your party have foolishly awakened an entity of limitless power and destruction: Xxubleks, otherwise known as "The Faceless King" or "The Lord of Slime". If you wish to survive, you must presently find your way out of this hellish dungeon. The demon has assumed the form of a massive, conical heap of slime, and it will not rest until you are destroyed. It is perhaps ten minutes behind you....
From the front cover:
An OSRIC mini-adventure designed for from four to six characters of 4th through 6th level.