Lich's Last Stand

Long ago, a powerful lich threatened the kingdom and was destroyed by mighty heroes. Though its phylactery could not be found, a powerful curse was laid upon the lich, trapping it inside its phylactery. This fading magic can’t hold the creature muchlonger, so the PCs must enter the phylactery itself in order to destroy the lich before it escapes back into the world.

Pgs. 144-149