Considered by many to be the first modern mystery novel, Trent's Last Case introduces the gentleman sleuth Philip Trent, a freelance reporter and investigator. Trent becomes involved in the case of the murder of millionaire American financier Sigsbee Manderson, slain while on holiday in England. During the course of his investigation, Trent falls in love with one of the primary suspects. And while he collects evidence and becomes convinced that he has cracked the case, he turns out to be well off the mark.