Lewis Powell attacked the Secretary of State William Stewart on Good Friday, 1865, as part of the Lincoln assassination plot, conspiring with John Wilkes Booth. He snuck into the house under the guise of a messenger bringing medicine for Stewart, who was recovering from a carriage accident. He stabbed the elderly and bed-ridden Secretary several times, but was fought off by the man's teenage daughter and a companion. He fled. Stewart would survive.

He looks like what he is--a carelessly handsome 18 year old boy--but even at that age, he was already a Confederate veteran with four years experience, wounded, captured, and released at Gettysburg and one of Mosby's famous mounted rangers. He was shy and introverted. His sister called him "Doc" because when he was a young boy, he liked to take care of stray, injured animals he found. Another anecdote from his teenage years was when he also almost stomped a young black maid to death for "talking back" to him. In his Confederate days, he was known as Lewis the Terrible for his ruthlessness in battle. He's the only one of the conspirators who worked desperately to exonerate the old woman who was also looped into the assassination plot for reasons of owning the boarding house Booth met in.

When he was finally captured after the assassination attempt, wandering the streets of Washington, DC in his bloody sweater, he was sentenced to death by hanging with the other Booth conspirators. His neck didn't break when the rope caught, and so he strangled to death for ten minutes. Later, his body got lost by the government. In 1991, his skull was found in the Native American anthropological storage space in the bowels of the Smithsonian. Some supporters of his took it to Florida, where he was born, and buried his head there in a hatbox.