Harry was a soldier in the British Army during World War I.
He was a friend of Jamie Colquhoun and was thinking of proposing to his sister, Jeanie Colquhoun, after the war.
He was sent back in time by a Weeping Angel on 21 August 1914, when he and Jamie were on a reconnaissance mission in the town of Mons. (COMIC: The Weeping Angels of Mons)