Harry was a friend of Shireen, and one of the group with whom Bill Potts moved in following the search for decent and affordable student accommodation. He attended the Twelfth Doctor's lectures, and liked him because of them. (TV: Knock Knock)
Harry began looking for student accommodation along with a few other students from St Luke's University. After an afternoon of disappointing offers from an estate agency, the Landlord approached them and offered them his massive house at 11 Cardinal Road for cheap rent. Harry was among the most enthusiastic of the group and greatly looked forward to moving in.
The night of moving in, he began noticing strange sounds in the walls. When he asked the Landlord about how to get into the tower, the Landlord sharply told him it was out of bounds.
When Bill referred to the Twelfth Doctor as her grandfather, Harry mentioned that his granddad and his grandfather's boyfriend were arrested in China after attempting to steal a section of the Great Wall of China.
When the house began seemingly coming to life, all the doors and windows sealed themselves shut. Harry and the Doctor tried to save Felicity but she was absorbed by the Dryads in the wood. Harry even saw the Dryads but he and the Doctor managed to escape before they could reach them. They then stumbled into the basement and found evidence of previous groups of children who had come to the house before, but were all devoured by the Dryads. The Landlord then appeared before them. Before he could continue, Harry finally gave in to fear and desperately tried to find a way out only to get his foot caught in the steps. The Landlord then summoned a swarm of Dryads who crawled over Harry and devoured him as he screamed in agony.
Harry was enthusiastic and curious, asking numerous questions during the tour of the house. While he seemed to be able to cope with the terrifying situation unfolding around him at first, he eventually snapped when he learned the Dryads intended to devour him. He then broke down into a fit of panic but calmed down once he was restored to life. (TV: Knock Knock)