It's a dreary October morning in Los Angeles. And it looks like it's about to rain.
Private detective Philip Marlowe pays a visit to millionaire General Sternwood. The dying General is being blackmailed by Arthur Geiger, who claims that Sternwood's daughter Carmen owes him gambling debts. And it's Marlowe's job to track down Geiger's whereabouts. During the meeting, Marlowe also senses that there is something fishy going on with the disappearance of Rusty Regan, the General's son-in-law and husband to Vivian. Rumor has it that Regan ran off with Mona Grant. So in a nutshell, there seem to be two main plotlines in the novel: (1) the blackmail scheme, and (2) the disappearance of Regan.
Let's start with the first plotline. Marlowe learns that Geiger's using his rare bookstore as a front for an illegal pornography racket. Later the same day, Geiger is murdered and Marlowe finds Carmen naked at the scene of the crime… yikes.
The next morning, another stiff surfaces, and this time it's Owen Taylor—the chauffeur. Apparently, Vivian is being blackmailed with nude photos of Carmen, and Marlowe traces the photos back to a Mr. Joe Brody. But before Marlowe is able to turn Brody in to the police, Carol Lundgren shows up out of nowhere and shoots Brody in the mistaken belief that Brody had killed Geiger. Don't worry if your head is spinning. Ours is, too. The plot is really convoluted and hard to follow, so you just have to go with the flow.
Okay now on to the second plotline. Marlowe's job is technically done now. He has exposed the blackmailers and the case should be closed. But Marlowe decides against his better judgment to find the truth behind Regan's disappearance. No one wants to help Marlowe, least of all Vivian, who owes gambling debts to Eddie Mars (who also happens to be Mona's husband, as in the gal who supposedly ran off with Regan. Talk about a love triangle…. or quadrangle…).
Enter Harry Jones. He has a scoop on Mona's whereabouts, but before Marlowe is able to get the necessary information, Harry is poisoned by Canino, Mars' right-hand man. Marlowe somehow manages to track down Mona, and a few fist fights and gunshots later, Marlowe has killed Canino and escaped with Mona.
The next day, Marlowe pays a visit to the General and runs into Carmen, who wants Marlowe to teach her how to shoot a gun. And then…. bang, bang, bang, bang, bang! Carmen fires five shots straight at Marlowe. But having already suspected Carmen of foul play, Marlowe had loaded the gun with blanks. Phew, close call.
Marlowe figures out that Carmen is the one who murdered Rusty, because he (like Marlowe) had also rejected her sexually. When Marlowe confronts Vivian, she confesses that Rusty is buried under an oil sump and that she had paid Mars to help her bury the body. At the end of the novel, Marlowe contemplates death—the "big sleep"—and concludes that death is the only escape from the nastiness and depravity of life.