The Mystery of Three Quarters

The Mystery of Three Quarters is a novel written by Sophie Hannah. It features Hercule Poirot.

Plot summary
Four people receive letters purporting to be from Hercule Poirot and accusing them each of the murder of Barnabas Pandy, a ninety-something businessman who drowned - accidentally, it seems - in his bath. Poirot has no knowledge of the letters, nor yet of the late Barnabas Pandy, until he is accosted by one of the recipients, society woman Sylvia Rule, before finding another, market trader John McCrodden, in his drawing room. As he begins to investigate the source of the letters with assistance from his young friend Edward Catchpool, a Scotland Yard detective, he comes into contact with the family of Pandy, which seems to be hiding secrets.

Main characters

 * Hercule Poirot, private detective
 * Edward Catchpool, inspector from Scotland Yard
 * Euphemia "Fee" Spring, Waitress at Pleasant's Café and Catchpool and Poirot's friend

Recipients of the letters

 * Hugo Dockerill, housemaster to Pandy's great-grandson
 * John McCrodden, seemingly unconnected to Pandy
 * Sylvia Rule, mother of a boy in the same school house as Pandy's great-grandson
 * Annabel Treadway, Barnabas Pandy's granddaughter

Other characters

 * Kingsbury, Pandy's butler and closest friend
 * Ivy Lavington, Treadway's niece
 * Lenore Lavington, Ivy's mother
 * Timothy Lavington, Lenore's son
 * Rowland "Rope" McCrodden, John's father, a solicitor nicknamed "Rowland Rope" due to his preference for capital punishment
 * Freddy Rule, Sylvia's son and Timothy's classmate
 * Mildred Rule, Sylvia's daughter

Explanation of the novel's title
Poirot refers to the case as "the mystery of three quarters" because, of the four people who received letters purporting to be from him, three are in some way connected to the late Barnabas Pandy, whose murder the letters accuse each one of. The fourth, however, is seemingly unconnected. Poirot, then, must figure out the relevance of the fourth person, or quarter. To symbolise the four quarters Poirot uses a slice of Church Window Cake, whose fourth square is separated from the other three.