It tells of a despondent French nobleman who decides the only thing to do is to go on a crusade to Jerusalem. He sets out with some fellow knights, slaves, and retainers, with neither map nor guidance. The novella depicts their journey across Europe, pillaging, raping, and murdering peasants and Jews along the way, while nightly praying for salvation, and growing increasingly frightened of a curse that they feel is upon them. Oz weaves an effective and engaging interplay of piety and depravity.
I think it affords several allegorical readings, but I haven't had time to formulate an interesting one yet. Do read it, it's excellent. It's been translated into quite a few languages, so those of you who can't read Hebrew are robbed of that excuse, at least.