Control ordered him to take a team to Siberia to find out more about possible time travel experiments being conducted at the Naryshkin Institute. When he arrived there, he started killing scientists to convince them to turn over their time machine.
However, the time disturbances in the area were a result of natural phenomena exacerbated by the presence of Maxwell Curtis. He finally realised the threat Maxwell posed to the entire Earth, and that the Eighth Doctor could stop it. Hartford sacrificed himself to let the Doctor escape, making Maxwell use his black hole abilities to crush Hartford to death. (PROSE: Time Zero)