Thomas was Isobel's husband and Catherine's father. He lived in Edinburgh in 1645.

Thomas sat with Catherine as she was dying from the bubonic plague, he even watched as the plague doctor removed her from their home. He later contracted the plague himself but was cured by the Twelfth Doctor with a tablet from the TARDIS.

He was soon reunited with his daughter after the Doctor cured her of the plague. (PROSE: Plague City)