In the novel Five Little Pigs, Carla Lemarchant (born Caroline Crale) is the daughter of Caroline and Amyas Crale. She is described as a "tall, slender young woman in the early twenties; the kind of young woman that one definitely looked at twice. Her head was well poised on her shoulders, she had a square brow, a sensitively cut nose, and a determined chin". She wants to know if her mother really did murder her father, so she contacts Hercule Poirot.
She is engaged to John Rattery.
In the ITV Agatha Christie's Poirot episode, Carla is renamed Lucy Lemarchant. In this version, she tries to kill the murderer of the case but then Poirot makes her change idea and put her revolver down.