Mrs Harris' husband was stationed elsewhere during the fighting. She took in billets. Corporal Jed Allum was one of her guests. She had received a notice announcing two new billets: Dr John Smith and Ace. The night they were due to arrive, Japanese submarines bombed the ships in the harbour, delaying the Doctor and Ace's arrival.
After they arrived, the Doctor left Ace behind. When Ace had gone upstairs to bed, Mrs Harris went outside and killed a chicken, unaware that Ace was watching her. She gutted the chicken so she could read the signs in the blood, feathers and hair.
After Ace had left, she returned, along with the Doctor and Li Chen Mei. Mrs Harris, who was trying to manipulate the "hymnal skein", or life force, to protect the city, was stopped by Mei. The Doctor explained that Mrs Harris could sense the life force but didn't have the understanding to manipulate it. (PROSE: Hymn of the City)