The movie opens when police officers arrested Bertrum T. Cates for teaching evolution in his biology class. They called this the beginning of the "Monkey Trial". Rachel Brown, the Reverend's daughter, came to see Cates while he was in custody. They had been seeing each other. While she was there, a reporter named Mr. Hornbeck came and told Cates that the Baltimore Herald was on his side. Meanwhile, the townspeople were protesting against Darwin's Theory. During the protests, Mathew Harrison Brady came and spoke against Cates. Rachel said that he was not a heathen. Also, the lawyer Henry Drummard was going to defend Cates. Preaching against them, Brady referred to Drummard as the devil and Cates as the devil's deciple. When Rachel tried to talk to her dad about Cates not being a bad man, he dropped to his knees begging for forgiveness and did not pay attention to her. When Drummard arrived at his hotel, he speaks with Brady and his wife Sarah. Apparently, Drummard and Brady had been friends and on the same side of many arguments before. .
When the trial started, Drummard excused a man on jury duty first off. He also insisted that they change Brady's title to the temporary honorary colonel. That night at dinner, Sarah Brady came over and sat with Henry Drummard and the talked about Brady. Also, Reverend Brown held a prayer meeting and condemned nonbelievers. Brady and Drummard spoke that night on the front porch. Brady told Drummard that the poor people of the town only had that religion to look to for hope, but Drummard said that it was giving the people false hopes.
During the trial the next day, the first witness was a young boy from Cates" class. Then, they called Rachel to the stand. She explained that Cates stopped attending her church when the Reverend condemned a boy, the Steppens boy, who got a cramp and drowned while swimming. Drummard brought in five scientists, but Brady objected.