The mysterious Mr. Arkadin claims he cannot remember anything of his life prior to the moment in 1927 when he found himself alone in Zurich with two hundred thousand Swiss francs in his pocket, a sum with which he subsequently built a vast fortune. Now a fabulously wealthy and influential financier, he enlists the services of one Van Stratten, a small-time smuggler and racketeer, charging him with the task of investigating Arkadin's forgotten past. Traveling across the world - and through the seedy underworld of postwar Europe - Van Stratten begins piecing together information for his confidential report. But for some unknown and sinisterly suspicious reason, everyone he speaks to soon turns up dead.