During the "Hartford" years, while his children were growing up, Mark Twain gained increasing fame and enjoyed the blessings of a happy home life. Dangerous Intimacy delves into the later years, after the death of his daughter Susie and that of his wife Livy. The documentary reveals how Twain, after Livy's death, enjoyed the attentions of Isabel Lyon, his flirtatious and calculating secretary. With the help of Twain's assistant, Ralph Ashcroft, Lyon exiled Twain's surviving daughter Jean, an epileptic, to a sanitarium and nearly succeeded in assuming control over Twain's household and estate. As Twain reflected bitterly in his still largely unpublished autobiography, the pair were conspiring to reduce him to "a stripped and forlorn King Lear". However, with the help of Standard Oil magnate Henry Rogers , who called for an audit of his affairs, Twain uncovered the plot in time. He called Jean home from exile and eperienced delight in her company for the months remaining in their lives. Jean died after a seizure on Christmas eve morning in 1909. Twain died soon after in April 1910.