Time as a policeman
In 1863, Tommy worked as a policeman in the Broadway Squad of the New York Police Force during the New York City draft riots. During the riots, he saved the life of several women as well as the singer Adelina Patti though he suffered several injuries in the process. During his recuperation, he met Horace Greeley, the founder and editor of the New-York Tribune. Horace was impressed by Tommy's actions, so he wrote an elogious article about him, which made him a hero. As a result, Tommy was invited to join the Pinkerton Agency, which he accepted.
Meeting Horace Greeley
In 1872, Tommy visited Horace in his home in Pleasantville, New York, who was on his death after being poisoned. As both of them reminisce their first encounter in 1863, Horace informed Tommy that someone in President Ulysses S. Grant's inner circle had poisoned him, leading to his death. He also told him that Grant was in possession of a precursor artifact, which he used to manipulate the elections.
During the conversation, Horace fell asleep so Tommy allows him to rest. He lets the nurse attends to him before leaving the room, though Greeley senses something amiss. He re-enters the room, managing to prevent the nurse from suffocating his friend to death. The nurse is later revealed to be a Templar agent and before Horace was able to fire his gun, the nurse throws a knife at him which leaves a cut on his face, before escaping through the window.
Tracking the Templar agent
Despite surving the incident, Horace later died and Tommy was tasked to investigate his death. Believing the agent to have fled to the United Kingdom, Tommy board a ship to investigate and along the journey, he met Mark Twain, a fellow American and author. The two discussed about Greeley, who had been a friend of both, and his murder. Twain offered to help him after hearing about the Pieces of Eden, of which he heard about during his travels.
Tommy and Mark tracked down the Templar agent to London, England, confronting her above the rooftops of the British Museum. Before he could arrest her, the agent attacks him and attaches a rope onto him and jumps off the building, pulling Tommy down with he and escaping in the process. Before he lost his grip, he was saved by the timely arrival of British Assassins Henry Green and Evie Frye, whom Frederick Abberline had seek asistance from. The next morning, the group met in the Scotland Yard morgue, where Frederick informed them that the Templar agent was a bait to lure them away from the museum so that her accomplice can search the museum. They studied the mud prints of Constable Niall Hobday, one of the museum guards and tracked the findings to a slaughterhouse.
At the slaughterhouse, they find Edward Feather, the Head Clerk of Acqusitions at the museum who is still alive but unconscious. They were confronted by the Templar agent, who brought the Blighters gang with her. A firefight ensues which ended with the group victorious though Tommy was almost killed in the process.
The agent however managed to obtain information from Feather and escaped to the museum. The group made their way there, discovering the dead watchmen left in her tracks. They proceed to the Acquisition Department, where they find the agent and Blighters rummaging through the cabinets, triggering another firefight. The agent found the documents she wanted attempts to flee again, before being confronted by Tommy and Evie. Faking surrender, the agent throws a smoke bomb, allowing her to escape again. Evie stayed behind to prevent a fire from occuring while Tommy goes after the agent, chasing after her on a carriage.
Chasing through London, Tommy was unsuccessful in his attempt and the agent escapes again. Believing that the agent will need to return to the States by ship, Tommy boards the ship in the final attempt to capture her. True enough, he confronted the agent on the ship's deck, who reveals her name as Alice. Alice offered him to join the Templar cause but Greyling refused and she threw the pages into the sea to prevent them from falling into the hands of the Assassins. Stating that she had grown fond of him, she warned him that his actions wouldn't go unoticed by her fellow Templars, before comitting suicide by jumping into the Atlantic.