From the front page of the adventure:
The WeavePasha of Almraiven seeks adventurers to recover shards of the Calimemnon Crystal. It seems as if one of the shards has practically come to him. Elemental disturbances in the abjuries he maintains have led the WeavePasha to believe that the shard has been brought to Almraiven, and is interfering with the magical defenses of the city. Other reports indicate the Twisted Rune, a highly secret cabal of powerful undead spellcasters, may be involved, though what they are up to remains a mystery. A Living Forgotten Realms adventure set in Calimshan for characters of the Paragon tier (levels 11-20). CALI4-1, CALI4-2 and CALI4-3 are playable in any order and collectively form the Calimemnon Crystal major quest.