In 1874, the Henry Ward Beecher scandal rocked America. Harriet's younger brother had become a symbol of Protestantism in America. He and his wife lived a comfortable existence with their ten children in Brooklyn and, like his sister Harriet, he was considered one of the foremost social advocates in the country. That year, a member of his church named Theodore Tilton accused Beecher of having an affair with Tilton's wife. He took Henry Beecher to civil court and the scandal grew into a media circus. In court, Tilton's wife changed her story almost daily. Isabella Beecher, Henry and Harriet's younger half-sister who at this time was suffering from mental illness, publicly insisted her brother was guilty. Despite Isabella's behavior, an ecclesiastical court found Henry innocent and he also won his civil case. The public stood behind him and his reputation was untarnished.
Harriet's husband, Calvin, was suffering from ill health. He had grown obese in his old age. Harriet tended to him in their Hartford home. In 1878, Harriet's last novel, Poganuc People, was published. It was semi-autobiographical, detailing the life of a bright young girl surrounded by family full of talented siblings. Meanwhile, the country was in the throes of the Industrial Revolution, and Harriet's previous books were falling out of favor amongst the literary community. The advent of realism in fiction meant that her contrived plots and romanticized characters were seen as sentimental. The social tracts she often put into the mouths of her characters were seen as heavy-handed. Despite these criticisms, Harriet Beecher Stowe remained a national treasure. In 1881, her seventieth birthday was a national event. During the festivities, she called the abolition of slavery the greatest event in her life.
Harriet's final book, a children's book titled A Dog's Mission, was published in 1881. Five years later, in 1886, Calvin died. The next year, Harriet's youngest son, Charles, wrote his mother's biography. As she grew older and frailer, Harriet became a recluse, failing even to attend church. She grew senile and was bedridden. Her neighbor, Mark Twain, visited her and tried to cheer her with his jokes.
On July 1, 1896, at the age of eighty-five, Harriet Beecher Stowe died. She was buried in Andover, Massachusetts next to her husband.