From the front cover:
Out of Body, Out of Mind is a d20 System adventure booster designed for 3-5 characters levels 4-6. It can be played as a stand-alone adventure or dropped into any ongoing campaign setting.
From the back cover:
Welcome to the youngest and most turbulent of realms, a mountainous expanse known as Tirna'cel. This place was once well known for its power-mongering warlords, magic-wielding sorcerers, and archfiends from the deepest pits of the Abyss. But in the last 600 years, this has changed. Tirna'cel is a peaceful and welcoming land now, due in no small part to the efforts of the warlord Tirna'gael, a member of the land's founding nobility.
Tirna'gael turned against the other rulers without warning, attacking and overwhelming them without remorse. He is said to have suddenly grown stronger and more powerful. The reasons for his remarkable gain in power are unknown, though they are routinely connected to items believed to have been entombed with him by the then-newly formed paladin's Order of Garadon.
After his death, Tirna'gael's body was interred in his central citadel, a large stone fortress suspended over an immense lava pit. There he has rested for nearly 600 years, protected by the surrounding hostile environmentand a small cadre of supernatural guardians summoned and permanently bound by the Order of Garadon.
But recently, rumors have reached the corridors of Tirna'cel's capital city that invaders have struck the fallen hero's burial place, in search of one or more of his legendary magic items. So far, all that is known of these foul creatures is that they are native to the environment, being resistant to the fiery dangers of the area.
Your party has been summoned by the lord of the realm, who has charged you with ending the threat to Tirna'gael's tomb and the potential destruction of the land's long-enduring peace. If the sources of Tirna'gael's power were to fall into the wrong hands, it could mean the end of the nation as you know it.