The Big Four

A mysterious, dust-covered man collapses in Poirot's bedroom, leaving behind a cryptic clue: the number 4, scrawled repeatedly. As Poirot delves into this puzzling incident, he navigates a web of international intrigue and danger. The story unfolds as he seeks to unravel the significance of the number and the identity of the man, all while risking his life in pursuit of the truth.