Frederick Garland is a photographer living in Victorian London. He has a small shop with living quarters attached, on Burton Street near the British Museum. He meets Sally in Swaleness and helps to hide her from Mrs. Holland. He gives her his card, which she uses to find him when she leaves Mrs. Rees' house. Sally needs help and has nowhere to go, so Frederick lets her stay with him and his sister Rosa. In return, Sally helps with the accounts and the business of the photography shop. Frederick helps Sally solve her mystery, and fights Mr. Berry at the end of the story.
