Samuel Langhorne Clemens (30 November 1835 – 21 April 1910), better known by his pen name Mark Twain, was an American author and humorist.
In 1872, Twain encountered the Pinkerton agent Tommy Greyling during a boat trip between New York City and London. The two discussed about Horace Greeley, who had been a friend of both, and his murder. Tommy had been sent in United Kingdom to investigate the crime and Twain offered to help him after hearing about the Pieces of Eden, of which he heard about during his travels.
A few days later, Greyling and Twain partnered with Detective Frederick Abberline and the Assassins Evie Frye and Henry Green, chasing the Templar agent who tried to murder Greeley across the city. The group tried to prevent Alice from stealing pages of the Voynich manuscript hidden in the British Museum. While they ultimately failed, Greyling later cornered Alice on the boat bringing her back to America.