New York cabbie Joe Benton and his Russian-born wife Anna have a loving marriage, despite their constant teasing. Joe and Anna's brother, Paul Roya, are both independent cab drivers who are at odds with the large Comet Cab Company. After Paul is beaten up by some Comet cabbies, he decides to be a "double agent" and infiltrate the company. Beecher, a labor agitator, is hired by Comet to foment trouble among the independents and secretly works with Buddy, a friend of Joe and Paul's. On the night of Anna's birthday, Anna, who is pregnant, asks Buddy to take a raincoat to Paul, who is working late. When Buddy turns up at the garage, Beecher is angry with him for being there, then takes the box with the raincoat from him. Meanwhile, the night watchman finds a bomb in the garage and, seeing Paul there, thinks that he is the bomber. He then shoots and kills Paul just before the bomb goes off, terrifying Buddy, who did not know that he would be involved in serious violence. At the inquest, Beecher accuses Anna of transporting the bomb to Paul in the box with the raincoat. Though District Attorney Gilbert does not believe that Anna is involved in the bombing, he feels that Beecher will use the incident to his political advantage, and so decides that Anna should be deported. At Paul's funeral, government men try to take her away, but she escapes, aided by her friends. Because they do not want her to be deported, all of her friends decide to take turns hiding her from the authorities. After some time, the district attorney, supported by the mayor, decides to offer amnesty to cabbies if they voluntarily turn Anna in. No one takes advantage of the offer, but soon detectives follow Joe to the home of Jim and Sophie Sloan, who are currently hiding Anna. Though the detectives only find Grandpa Sloan in the house, they know that Anna has been there, and the district attorney decides that he will arrest all of the cabbies for the bombing. Anna cannot stand to think of her friends suffering to protect her, so she calls the mayor to see if his amnesty offer is still available. When he says yes, she tells him where she is staying and waits for the authorities. At the boat that will take her back to Europe, Joe comes to visit Anna and promises to meet her there, but she tells him that she wants him to stay in America. When he leaves, he and his friend, Mike Edwards, find Buddy and discover that he is being paid to keep quiet about the bombing. They then force him to come with them while they look for the mayor and the district attorney. They track the mayor down at Jack Dempsey's restaurant, where he and the district attorney are attending a banquet with a number of famous athletes. After Joe and Mike force Buddy to confess in front of the dignitaries, Joe pleads with the mayor to do something quickly to save Anna. Everyone at the banquet then rushes to the pier, where they arrive just before the boat is about to sail. As Anna is being taken away from the boat, she says that she is about to give birth and an ambulance is summoned. While she is giving birth, the Comet cabbies decide to teach the independent cabbies a lesson, and a fight breaks out in which the mayor, Dempsey and other athletes join Joe in teaching the Comet cabbies a lesson. A few days later, when Joe and Anna christen their baby, he is given dozens of names to honor all of their friends.