"The Vanishing Comrade: A Mystery Story for Girls" by Ethel Cook Eliot is a mystery novel written in the early 20th century. The story revolves around a young girl named Kate Marshall, who is set to spend the summer with her estranged Great Aunt Katherine in Oakdale, where she is to meet her cousin, Elsie. The novel hints at themes of family dynamics, unexpected mysteries, and the complexities of friendship as Kate navigates her new surroundings and relationships. The opening of the story introduces Kate as she embarks on her journey to her aunt's home, filled with excitement for the summer ahead. The initial interactions with the Hart twins, her school friends, showcase Kate's vibrant personality and adventurous spirit. Upon arriving at Aunt Katherine's house, Kate's anticipation quickly turns to confusion as she meets Elsie, who responds to her with unexpected coolness. This sets the stage for the contrasts in their personalities and the troubled family history, particularly the mystery surrounding the orchard house, which holds secrets that will challenge their relationship. As Kate settles into her new environment, the reader is drawn into the complexities of her family ties and the enigmas waiting to unfold. (This is an automatically generated summary.)