Soon after returning home from the war, Chris Keller confides in his father Joe that he intends to marry childhood friend Ann Deever and move to Chicago. Joe, the self-made head of a successful manufacturing firm, is hurt by this revelation, as he intended for Chris to eventually take over management of the factory. He is also concerned that Chris's mother Kate will take the news badly, as Ann was engaged to Chris's older brother Larry, who was declared missing during the war and is presumed dead, a fact Kate refuses to accept. When Ann arrives that afternoon from Chicago, several of the Kellers' neighbors inquire about her father Herbert, Joe's former business partner, who is in jail. During the war, Joe and Herb's factory shipped out defective airplane parts, which caused twenty-one Army planes to crash in the Pacific. Joe was acquitted, but Herb was found guilty of authorizing the shipment, knowing that the parts were defective. That evening, Joe takes the family to dinner to celebrate Ann's return, but their meal is interrupted by Mrs. Hamilton, a war widow, who drunkenly calls Joe a murderer. Back home, Joe berates Ann for moving away and not facing her father's guilt and she admits she stopped writing Herb after finding out about Larry's death. Later, Chris and Ann take a drive together and when Chris proposes, Ann accepts, while expressing concern over Kate's reaction. During their absence, Ann's brother George, an attorney, telephones her after visiting Herb. Joe and Kate worry about the call, as Herb has always maintained that Joe was to blame for shipping the defective parts. The next day, Ann discovers George is at the train station and Kate fears he has found some reason to reopen the trial against Joe. When Ann goes to pick up George, a neighbor, Sue Bayless, remarks to Chris that the whole town believes Joe outsmarted Herb and considers him guilty. Chris is stunned as he has never doubted his father's version of events. When George arrives, he demands that Ann return with him and refuses to approve her marrying Chris. George is now convinced that Joe lied and that Herb is innocent but Kate reminds him of the long friendship between the two families and persuades him to stay to dinner. During the meal, Joe recalls that Herb always had difficulty accepting responsibility and chronicles his own life-long dedication to hard work. When Joe boasts that he has never so much as been out sick a day, George asks him about the one day Joe did not come to the factory, the day the defective equipment was shipped. As Joe hesitates, Chris begins to doubt his father for the first time. Infuriated that Joe and Kate have tried to dissuade him from believing in his father's innocence, George storms out and Ann goes with him, despite Chris's protests. Upset by the events, Chris visits Herb in jail and at his request, Herb relates the events leading up to the day of the shipment: After receiving important government war contracts, Joe has the factory running twenty-four hours a day and, to further expedite production, cuts down on the quality of the materials. Only after the bulk of the cylinders is complete, do tests reveal the steel as too fine and unable to perform adequately. When Herb informs Joe, he protests that they are obligated to fulfill their contracts and that fixing the process will bankrupt the company. If any problems result, Joe explains, they can claim to be unaware of the defect. The following day Joe calls in sick and when the Army representatives demand their shipments, Herb telephones for instructions. Joe tells him to make the shipment and that he will assume responsibility. Herb authorizes the shipment but at the trial Joe refutes his claim. Back at the Kellers', Ann returns to inform Kate that she intends to marry Chris. Kate insists that Ann has no right as there is no proof of Larry's death, but Ann presents her with a letter from Larry written just before his final mission. After reading the letter, Kate breaks down and pleads with Ann not to show it to Joe. Meanwhile, Chris leaves the jail to pick up Joe from his weekly card game. Afterward, Chris presses his father to explain Herb's chronicle and Joe states that he had no recourse but to make the shipment, as the entire family fortune which he had spent his life amassing, was tied up in the company. Distraught, Chris strikes Joe and flees. Later that night, as Kate and Joe sit waiting for Chris to return, Kate pleads with Joe to admit his error. Joe insists his actions were justified because he was protecting his family. Ann, searching for Chris, finds him at the place where he proposed and he admits Joe's guilt but maintains that his father truly does not understand the impact of his actions. Ann then gives Chris Larry's letter, and after reading it, Chris returns home to confront his father. When Chris begins reading the letter out loud to Joe, Kate tries in vain to intercede. The letter describes how Larry read news accounts of the factory's faulty equipment, the resulting Army Air force deaths and Joe and Herb's trial. He finds Joe's betrayal unbearable and in shame intends to make sure he does not return from his next mission. Joe admits that he always knew his guilt included Larry's death, and now realizes that all those who died were equally his sons. He retreats to his room and shoots himself. A few days later, Chris and Ann depart for Chicago with Kate's blessing.