Samuel Karnish's life is a mess and reeling out of control. By chance he meets an Hasidic couple, the Brenner's, while flying to Houston for his best friend's third wedding. Sam who is a "half Jew" ("What is this mathematics?" asks Brenner) is confronted with his own belief system as this unlikely encounter turns into a friendship, of sorts. OK, he is attracted to Aaron Brenner's very shy, but enigmatic wife. But he really does like Aaron for his intelligence and certainty. So there lies some of the complication.
All in all we follow Samuel through some interesting events as his job, girlfriend, and well everything, bottoms out. There's much humor here and lots of philosophy about the Hebrew faith or any faith for that matter.