The serum from Paris proves ineffective, and the plague turns pneumonic. Rieux thinks that his wife is lying about the state of her health in her telegrams. Tarrou draws up a plan to recruit volunteers for the sanitation league because he does not want to see anyone condemned to death by compulsory service. Rieux would be grateful for the help, but he asks Tarrou if he has weighed the dangers. When Tarrou asks for his opinion on Paneloux's sermon, Rieux states that the plague victims' suffering makes him detest the idea of "collective punishment." Tarrou believes that human catastrophes have a positive side because they force people to "rise above themselves." When Tarrou asks if he believes in God, Rieux avoids the question by explaining that Paneloux has not seen the suffering first hand, so he has the luxury of believing in "Truth." Rieux believes that it might be best to cease believing in God and to throw all efforts into defying death. Although such efforts might be useless, he sees no reason for giving up.
Although Tarrou's plan proves effective, Rieux hesitates to exaggerate the importance of the volunteers' efforts because it makes them seem like rare occurrences. He believes that people are basically good, and that ignorance is their worst vice. The volunteers realize that the plague is everyone's concern, so they do their duty by helping to fight it. Doctor Castel begins making serum using the local bacillus microbe. Grand becomes a general secretary for the sanitation league. Rieux muses that many readers will require a "hero," so he offers Grand as an "insignificant and obscure hero."
When Rambert begins investigating illegal methods of escape, Cottard offers to help him. Cottard has become a smuggler, and he has made many acquaintances in the criminal underworld that has profited from the plague. He brings Rambert ever deeper through the criminal underworld, until he meets someone who is able to help. Rambert has to wait two days while his escape is arranged, so he contacts Dr. Rieux to update him on his endeavors. Dr. Rieux is tired because there is a constant shortage of equipment and manpower to fight the plague. A snag delays Rambert's escape again, but eventually all is in place: two sentries, Marcel and Louis, agree to smuggle him out in return for 10,000 francs.
When Tarrou suggests that Rambert might be useful in the anti-plague efforts, Rambert becomes taciturn and obstinate. Moreover, his escape plan again hits a snag when Marcel and Louis miss their appointment to meet him the next day. He has to start over again, and goes back to Cottard. Cottard remarks to Tarrou that the efforts of the sanitation league are useless because they don't seem to be making much difference. Tarrou insists that it is every able-bodied man's duty to help fight the plague and asks Cottard to join the league. Cottard refuses because "it's not [his] job." He would have been arrested for a crime he committed in the past were it not for the plague.
Rambert reveals that he stopped believing in heroism after taking part in the Spanish Civil War on the losing side. When he states that Tarrou is capable of dying for an idea, Rieux asserts, "Man isn't an idea." Rambert retorts that man is an idea if he is incapable of love. Rieux insists that fighting the plague isn't heroic, but a matter of "common decency." Tarrou draws Rambert aside to inform him that Rieux's wife is in a sanitarium 100 miles away from the city. Chagrined, Rambert offers to join the sanitation league until he can escape.
The pneumonic form of the bubonic plague is transmissible via airborne contagion. It is also far more deadly than the form that is transmitted via fleas. Therefore, despite the best efforts of men like Rieux, they are facing defeat in the anti-plague struggle.