Agatha Christie's debut novel was the first to feature Hercule Poirot, her famously eccentric Belgian detective. The Mysterious Affair at Styles is a detective novel by Agatha Christie. It was written in the middle of the First World War, in 1916. Styles was Christie's first published novel & introduced Hercule Poirot, Inspector (later, Chief Inspector) Japp, and Arthur Hastings. Poirot, a Belgian refugee of the Great War, is settling in England near the home of Emily Inglethorp, who helped him to his new life. His friend Hastings arrives as a guest at her home. When Mrs Inglethorp is murdered, Poirot uses his detective skills to solve the mystery.