Mabel West, daughter of the famed mystery novelist Raymond West, defies her father's wishes for a conventional life. Instead, she aspires to become a renowned detective and heads to London to assist the legendary Hercule Poirot, the esteemed Belgian sleuth based in the city. After earning her father's hesitant blessing, Mabel delves into a thrilling world of enigmas and danger, with the condition that she visits her great-aunt, Jane Marple, in the quaint village of St. Mary Mead from time to time.