Book: The Big Four They are formidable enemies in their own rights: a French scientist, an American millionaire, a brilliant Chinese gentleman, and a master of disguise. But together they are the Big Four, a partnership with one simple goal--murder. Hercule Poirot has never come up against an opponent so vicious . . . or so deadly.
An emaciated stranger approaches Hercule Poirot, shouts a warning about "the big four" and drops dead. Who knew Poirot's inquiry into the man's odd behavior would lead to an underground laboratory, an insane asylum, and rumors of a secret weapon?