From the introduction:
Crysothrax is a Fallen cleric of Bahamut. A weak and venal silver dragon, he has never been able to resist temptation, even in the service of the Platinum Dragon himself. Gold, power, magic – all have turned his head at one time or another, and despite his guilt afterwards has always gone back to his errant ways. Now approaching middle age (for his kind) he is looking for a way out. Crysothrax came to Sigil a decade ago where he found a curious sect of worshippers of Pelor who believe that if they attain a state of Grace at any point in their lives, then their souls will remain in that state for eternity, granting them access to Celestia as petitioners when they die. In the planes belief is power, and if enough believe then it is so. Crysothrax saw his chance – if he can achieve a state of grace, he may yet be pass into heaven. Unlike the rest of the sect, Crysthrax has elected to pursue Grace not through purity of his soul, but by cheating. He has decided that he will purify and sanctify his soul through external means. For this he seeks two items; an apple from the gardens of purity in Arborea, whose flesh is so pure that a soul is cleansed of its impurities at its merest taste, and a Holy Wafer from the bakeries of Mount Celestia – the food of the saints which will sanctify any soul that they touch. With these two he can guarantee that he will be able to enter Heaven when he dies, and he can return to giving in to his temptations once more.
Alas, as a powerful dragon, and a fallen cleric at that, Crysothrax could no more enter the Upper Planes undetected than could a Barbazu befriend a Guardinal, so he seeks adventurers to do it for him, preferably expendable, not too powerful, and with few scruples.