Inasmuch as The Crying of Lot 49
has a plot, it's about a suburban housewife, Oedipa Mass (all the characters in this book have pun-ny names like that) who, after being named the executor of her wealthy ex-boyfriend's will, discovers a secret society connected by an underground mail service. Or, she becomes a delusional paranoid. Either reading is possible.
This is a trippy book. It was written in the 60s, and it's Pynchon's shortest, but that doesn't make it a particularly easy read. I can see why it's highly regarded among the literati -- Pynchon writes imaginatively and inimitably, and the structure of the novel is deep but very straightforward. The plot, however, is not. This is the sort of book you probably have to read several times to "get." I kind of have a love-hate relationship with it after reading it -- I am not usually a big fan of literary fiction that emphasizes style over substance, but there is substance here. I'm just afraid a lot of it went over my head (and I'm usually a pretty deep reader).
Fans of conspiracy thrillers, particularly Robert Shea and Robert Wilson's Illuminatus!
trilogy or Neal Stephenson's The Baroque Cycle
would do well to check out The Crying of Lot 49
, since it's very much in that genre, but whereas the former two are more overtly conspiratorial and science fictional, the conflict in The Crying of Lot 49
is mostly internal, involving the main character, Oedipa.