The story of The Custom Mary involves two preachers and a scientist, who discover two drops of Jesus Christ's blood. They use this material to clone Christ and to impregnate the young Mary with Christ's DNA. Along the way, Mary becomes involved with a lowrider mechanic named Joe, but their relationship is tested when Mary's pregnancy does not go as planned. Mary undergoes a transformation of faith, while finding new relationships on the dangerous streets of East Los Angeles.