In the short story The Case of the Perfect Maid, Gladys “Gladdie” Holmes was a cousin of Miss Marple's maid Edna. Gladys worked as a maid for a pair of sisters, Lavinia and Emily Skinner who were tenants at Old Hall in St. Mary Mead. At the beginning of the story, Gladys was given notice by Miss Lavinia to leave. There had been a number of incidents at the Skinners. First, Emily's brooch had gone missing. Gladys found it later in a drawer but Lavinia believed that Galdys had only put it there and claimed to find it when the police were about to be called. Then later, Gladys had broken a plate.
Edna asked Miss Marple to help. Miss Marple did not like Gladys. She found her "bouncing" and "self-opinionated". Nonetheless, Miss Marple knew her family and was convinced about her honesty. She therefore set out to prove her honesty.
In the NHK anime adaptation The Perfect Maid, Gladys is voiced by Kazusa Murai. It is not stated whether or not she is the cousin of Edna. Edna does not appear in this episode although she does appear in several other episodes as Miss Marple's regular maid. Here Gladys is a friend of Mabel West. Mabel has just arrived to visit Miss Marple and meets Gladys leaving Old Hall after being dismissed.