Marlowe wakes up in the morning, disgusted by women. He gets dressed and walks outside to into a rain-filled day, only to realize that the gray Plymouth sedan that had been tailing him is parked across the street. He runs through his mind, wondering who might be in the car. When Marlowe gets to his office building, he confronts the man in the Plymouth, who has followed him the whole way, and tells him that if he has anything to say he can go upstairs and talk to Marlowe in his office. In characteristic style, he leaves the man behind and walks up to his office to find a check for $500 from General Sternwood. The buzzer rings and the little man from the Plymouth appears. His name is Harry Jones.
Harry Jones has information that he is willing to sell Marlowe for $200. Marlowe guesses that Agnes Lozelle is somehow involved in this offer. Jones's information is that Mona Grant did not run away with Regan, but that she is instead being kept in a hideout by Eddie Mars so that everyone will keep on believing Regan ran off with her.
Jones also brings Lash Canino, Mars's gunman, into the picture. Jones says that he came about this information through Joe Brody, who was investigating the Regan-Mona situation because he was trying to make money off of it. Amidst it all he saw Mrs. Regan in a car with Canino. Mrs. Regan knows Canino and Canino is Mars's friend. Therefore, Joe Brody came to the conclusion that Canino knows something about Regan and is trying to make his own money off of the situation.
Agnes stumbled upon Mona Grant by coincidence. Jones says that Agnes will tell Marlowe where Mona's hideout is when he gives Agnes the money. Marlowe does not quite understand why or how Harry and Agnes are doing this. Jones responds, "[Agnes is] a grifter, shamus. I'm a grifter. We're all grifters. So we sell each other out for a nickel." Jones tells Marlowe to bring the money to the office—Puss Walgreen's office, which fronts as an insurance company, and which we have already heard of through Brody. Once Jones has the money, he will take Marlowe to Agnes, who will hand over the information.
At 7:00 that evening, Marlowe makes his way to Puss Walgreen's office. As he approaches he hears talking coming from the office. Canino is inside. Marlowe enters quietly through the adjacent door and overhears the conversation. Canino wants to know why Jones's Plymouth has been following the detective around. Mars knows about it, he says, and Mars wants an explanation. Jones tells Canino he is trying to blackmail Marlowe for money for Agnes's drug habit, because Jones has information about Carmen Sternwood's whereabouts on the night of Brody's murder. Jones knows that Carmen had been at Geiger's and had also attempted to shoot Brody because of a photograph of her he had in his possession. Jones tires to convince Canino that the fact he is following Marlowe has nothing to do with Mars.
Canino asks Jones where Agnes is. Jones will not give up the information, so Canino points a gun at him. Finally, Jones gives Canino an address, and it initially seems Canino is going to let it go at that. However, before he leaves, Canino offers Jones a drink. The drink is poisoned with cyanide, and Jones drops to the floor, dead. Marlowe waits until Canino leaves, at which time he goes into the office and discovers Jones's dead body.
Marlowe reaches for the phone book and attempts to confirm Agnes's location, the one Jones gave to Canino. It turns out there is no Agnes at that location; Jones had protected Agnes and given the wrong address. Marlowe admires Jones for this. Soon after Marlowe hangs up, the phone rings, and it is Agnes. Marlowe tells her that a man named Canino passed by the office, and that Jones got scared and ran. Marlowe and Agnes set up a meeting place to exchange the money for the information she holds about Mona Grant.
Agnes and Marlowe meet in a parking lot, the place they have designated. She tells him where Mona is hidden: east of Realito, where a road turns towards the foothills, near a cyanide plant, off the highway, next door to a garage and paintshop run by a man named Art Huck. Agnes discovered Mona's location one day when she and Joe Brody were driving. They saw Canino in a car with Eddie Mars's wife, so they followed her.
Marlowe leaves Agnes and makes his way to the location she just described. Driving on the highway on his way there, he runs into tacks on the street that give him two flat tires. From the spot where the car has broken down he can see a light that might be the light of Art Huck's garage. Marlowe walks up to the garage with the gun he took from the masked man who assaulted Vivian.
Under the pretense that he needs his flat tires repaired, Marlowe knocks on the door of Art Huck's garage. Canino's car is in the driveway. Art hesitates to let Marlowe in, and only does so at Canino's request. Canino tells Art to help Marlowe with his tires. There is an exchange of looks and glances between Canino and Art, after which Art reluctantly agrees to fix the tires. Next, Canino offers Marlowe a drink—Marlowe notes that there is no cyanide in this glass. However, before Marlowe knows it, Canino and Art have ganged up on him and are attacking him. As he does not see it coming, he is beaten.
The new character in this section, Harry Jones, commits one of the only genuinely good acts taken by any of the characters, aside from Marlowe. Much like the respect Lundgren pays to Geiger's dead body, Jones's refusal to give away Agnes's true location, even under gunpoint, is admirable. Marlowe is moved by Jones's action, saying that Jones may have died like a rat, but that Jones is not a rat in his eyes. Jones, in short, is not one of those "rats behind the wainscoting"—he has no veneer. He is merely a common criminal, who, nevertheless, is capable of some good. As Marlowe has claimed earlier, however, perhaps this is not a world for knightly deeds—for Harry Jones has ended up dead.
Agnes appears again, once again in collaboration with a man in another ploy for money. In this regard, it is questionable whether Agnes's seeming plight as a victim is actually merited. She does not have to continue to involve herself in a case via another ploy; however, when her drug habit is revealed, we suddenly understand her motive and financial desperation. This revelation may place Agnes further into the archetype of victim or it may illustrate that she has free will and has chosen her track in life. Agnes tells Marlowe, "wish me luck I got a raw deal." Whether her plight is a result of her choices or not, it has social implications. Indeed, the characters of Agnes—and Harry Jones—though minor, should not be ignored. Jones, unlike Agnes, admits to his choices in life: he says that he is a "grifter." This admission points to the fact that not all the characters in the book are two-faced; though many, if not all, are criminals in one way or the other, this classification cannot be seen in simple black and white, as there are many shades and gray areas.
For the first time in The Big Sleep, the hero appears to be defeated. Marlowe is beaten to a pulp, caught off guard and unable to defend himself. It is quite possible that a knight cannot fight back if he does not understand his role. Moreover, perhaps the fact that, as the story has progressed, Marlowe has become disillusioned, hurting his ability to fight back. Perhaps he needs to become the idealist knight once again, in order to win the war, even if he has lost a small battle. Alternatively, perhaps he needs to shed a layer of idealism and grasp or accept the cynicism of the world in which he lives. Perhaps he needs to be reinvigorated—in this case by Silver-Wig, who, as we see later, may reinforce a faith in humanity. Or, Marlowe's defeat may merely point to the fact that he is not invincible—that nobody is, and that, if not tainted by crime, then one is sometimes defeated in the world Marlowe inhabits. In short, there are numerous possible readings for this minor defeat, which do not work to the exclusion of others.