At a meeting of taxi drivers, a union official urges a committee of six men not to call a strike. Voices from the audience call out for Lefty, who was elected chairman of this strike committee, but Lefty has mysteriously disappeared. The union official, Fatt, and his Henchman threaten the union members and call those urging a strike “reds” (that is, communists). One of the committee members, Joe Mitchell, gets up and makes an impassioned plea for the strike. He starts to describe an encounter with his wife, Edna, which is then enacted onstage. The committee remains onstage in the background, where it comments as a chorus on the action it observes.

Joe comes home from a hard day driving a cab to find that the furniture he and Edna have been buying on installment has been repossessed and that Edna has had to put their two children to bed hungry. Edna accuses Joe of belonging to a union that is run by racketeers, urges him to start his own honest union, and threatens to go back to her old boyfriend. The chorus of committee members in the darkened semicircle beyond Joe and Edna comments that she will. Joe exits, saying he is going to look for another taxi driver, Lefty Costello, who was recently making statements similar to Edna’s.

In a flashback, Miller, another one of the committee members, encounters Mr. Fayette, an industrialist. Fayette gives a raise to Miller, then a lab assistant, and moves him to a new project, working with a Dr. Brenner to manufacture poison gas. Fayette also asks Miller to send him secret weekly reports on Dr. Brenner. Miller balks at what he calls spying, but Fayette warns him to think of the consequences of refusing—the chorus comments that he will lose his job. Fayette then fires Miller, and Miller punches Fayette in the mouth.

Florence is at home with her brother Irv. She is waiting for another member of the strike committee, Sid Stein, to pick her up and take her to a dance. Irv argues that Florence should stop seeing Sid, because his job as a taxi driver does not pay him enough to support them. Florence insists that she loves Sid, but she promises her brother she will talk to him about his prospects. Sid and Florence have been engaged for three years, unable to marry because of their financial commitments to their families. When he arrives, Sid tells Florence that the deck is stacked against people like them in the current depression. Sid tells Florence goodbye, but the scene ends with Florence burying her face in her hands and Sid on his knees with his face in her lap.

At the union meeting, Fatt is still berating the strike committee. He calls up a member of the audience, Tom Clayton, who Fatt says comes from Philadelphia, where the union recently attempted a strike. Fatt asks Clayton to tell the committee what happened as a result. Clayton claims that the union should listen to Fatt, that the time is wrong for a strike. Suddenly, a voice from the audience shouts out for Clayton to sit down, and, after a brief struggle, the heckler rushes onstage to announce that Clayton is an imposter: His real name is Clancy, and he is a company spy. Fatt tries to have the accuser thrown out, but he continues his accusations: Clayton has been a company spy for years, breaking up unions across the country. When Clayton denies these accusations, the accuser says that he knows the truth because Clayton is his own brother. Clayton escapes down the center aisle.

One of the committee members, Benjamin, helped the man from the audience make his case. He enacts an incident from his earlier career as a surgeon. Benjamin has been removed from an operation at the last minute by a Dr. Leeds. He comes into the office of Dr. Barnes to complain that Leeds is incompetent. Barnes explains the switch by telling Benjamin that Leeds is the nephew of a powerful senator. Moreover, the woman Benjamin was to have operated on is a charity case, and they are about to close the charity ward entirely to save money. Worse, Benjamin himself is going to be let go. Benjamin knows why: He is Jewish, and he has met this prejudice before. The phone rings, and Barnes announces that the woman has died on the operating table. Benjamin says he will get a job driving a cab and help change the United States. He raises his clenched fist.

Back at the strike committee meeting, another member, Agate Keller, has risen to speak, Despite Fatt and his henchman’s attempts to silence him, the audience urges him on. Agate’s weapon is sarcasm: He knows their union is fine, he says, but when he tried to put on his coat today, he discovered his union button was on fire for shame. Fatt and his gunman try to remove Agate physically, but other committee members intervene, and Agate continues. It is a question of class warfare, Agate says: The bosses will do anything to deflate wages and prevent strikes. Joe and the others from earlier scenes—Edna, Sid, Florrie, and Doc Barnes—need to join the struggle. Suddenly, a man dashes up the center aisle to announce that Lefty has been found with a bullet in his head. The play ends with triumphant calls for a strike.