Poirot's fastidious logic and Marple's quiet certainty don't just survive the anime treatment, they sharpen in it, their personalities the actual architecture of how mysteries get solved. Mabel between them becomes the reader's permission slip to ask the questions they're already asking. The show trusts you to solve it alongside them instead of explaining everything twice.

Mabel West rejects her father's hopes that she will lead a quiet, ordinary life. Set on becoming a great detective, she heads to London to work as an assistant to Hercule Poirot, the renowned Belgian investigator who lives there. Her father Raymond, a mystery writer himself, eventually gives his grudging consent on one condition: every so often, Mabel must visit her great-aunt, Jane Marple, in the small village of St. Mary Mead. Drawn from Agatha Christie's novels, the mystery series adapts 39 cases from the Poirot and Marple stories, with Mabel created as an original character to link the two detectives.