This is a tough one to review. Both due to content and preconceptions. While exploring similar themes (genetics, sexual intrigue, early Islamic history+theology), forms (capsule biography, footnotes, fragments), and style as some of the short stores in the superlative Codon, this novella feels more like notes for those pieces that it does an expanded, standalone effort.
Episcript largely follows the fates and personalities peopling the Abbasid court under al-Muktafi and his intentionally incompetent son al-Muqtadir. There's a lot to absorb (and learn) here, akin to Wikipedia with better, spookier prose, but it also means the only "plot" is the course of history, which can be read in all sorts of other sources, including primary sources like Tarikh al-Tabari, Tarikh al-Umum wa al-Muluk (تاريخ الطبري) History of the Prophets and Kings.
Highly recommended for anyone already minimally familiar with the Abbasid or Qarmatian states, but as far as (experimental) prose goes, I'd stick with the aforementioned Codon.