Tommy & Tuppence Beresford
These are the only detectives of Christie's that are actually married. We also see them through their years as they experience full life. The first novel in which they appear (the second that Christie wrote) is titled The Secret Adversary. Young Tuppence (formerly known as Prudence Cowley) works at an officer's hospital during the war, while Thomas is a young lieutenant in the military, having traveled around the world. He meets his childhood friend Tuppence after released from service, and they start the Young Adventurers Ltd., advertising "Willing to do anything, go anywhere. Pay must be good. No unreasonable offer refused." From that they get stuck into a plot that could ruin the government and they end up in dangerous espionage, to finally succeed and foil the enemy. (One of J. D. Hobbs' absolute favorites!)
They then get married and six years pass. Tommy has a desk job with the British Secret Service, and Tuppence is at home. The chief of British Intelligence--Mr. Carter, as seen in the previous novel--invites them to take over the International Detective Agency (as seen in the excellent short story collection, Partners in Crime). This detective bureau (headed by one Theodore Blunt to spy for the Bolsheviks) was in need of a new head; Carter asks Tommy to impersonate Mr. Blunt and to simply: 1) solve crimes and to 2) report any communist activity in England. Aiding the new Mr. Blunt is Tuppence, who takes on the role of his confidential secretary, Miss Robinson.
Tuppence came up with their slogan--"Blunt's Brilliant Detectives"--which quite stuck with them throughout the short stories. The stories were parodies of fictional detectives known to the reading public of the 1920's. In each story, Tommy and Tuppence would assume the methods/mannerisms of famous detectives/detective teams of literature. Tommy explained it like this: "You see, Tuppence, I can't help feeling that we are more or less amateurs at this business--of course amateurs in one sense we cannot help being, but it would do no harm to acquire the technique, so to speak. These books are detective stories by the leading masters of the art. I intend to try different styles, and compare results." In their adventures chronicled in Partners in Crime, they have "solved four baffling murder mysteries, rounded up a gang of counterfeiters, ditto gang of smugglers . . . one jewel robbery, two escapes from violent death, one case of missing lady reducing her figure, one young girl befriended, an alibi successfully exploded, and alas! one case where we made utter fools of ourselves. On the whole, jolly good! We're very clever, I think."
In their middle years, they're thirsting for more adventure and have a desire to aid the war effort of WWII. They get another assignment from British Intelligence to discover the identity of a Nazi spy in N or M? Both Tommy and Tuppence have their 'his/her' roles in their tracking down the spy, which ends up in a fantastic twist at the end of the novel. They appear almost thirty years later in the novel By the Pricking of My Thumbs (a line taken from Shakespeare's Macbeth). In this novel, Tommy and Tuppence uncover a secret about a house familiar to Tuppence, connected with a painting given to Tommy's aunt. The novel ends in quite an unexpected twist.
By the end of their crime-fighting careers, they've grown old and read letters from their twins Derek and Deborah, and adopted daughter Betty. Their fifth and last novel, Postern of Fate, was the last novel written by Agatha Christie and published in 1974. Now elderly, Tommy and Tuppence have retired and moved to a resort town, complete with a Manchester terrier named Hannibal. Tuppence and Tommy end up discovering the death of a young boy there in connection with the selling of submarine plans to a foreign government sixty years in the past. If the reader observes closely, he or she will notice Agatha Christie recalling her own childhood in the novel through locations and objects.
Featured in all of the Beresford stories is Albert Batt. Albert first met Tommy & Tuppence as an elevator/lift boy in the novel The Secret Adversary. He then became the office boy for their International Detective Agency and also managed the Duck and Dog pub. Years later, he returned to the Beresfords as their butler and friend (although he burns their dinners!). He sticks to his intuition and has proven himself worthy to his employers by finding clues, although he "was not given to the exercise of deep reasoning". The problem is he thinks up too many wild ideas about criminals (from detective fiction) at which Tommy scoffs and says: "Oh, be your age, Albert. You've outgrown that sort of stuff years ago!"
Tuppence Beresford is the one who always rushes into things without common sense, although she displays great intuition (like Albert) and intelligence, not to mention pride. When Tuppence is on a hunch, she's "like a terrier on the scent". Tommy, however, is a slow thinker and loves to take his time in making decisions. He likes to be sure of the situation before acting quickly, unlike his wife Tuppence. Mr. Carter, the British Intelligence Chief, once described the Beresford couple as "pace and stamina".