Alan Carr explores the story behind Hercule Poirot, trying on one of David Suchet's costumes from the TV adaptations and mastering the tricks between the Belgian sleuth's distinctive walk and trademark moustache. Alan also attends an immersive theatre production of Witness for the Prosecution with Robert Rinder.

Alan Carr visits the locations that inspired the creation of Miss Marple, meeting Coronation Street's Susie Blake as she prepares to play the venerable spinster sleuth on stage. Alan and Richard Coles also discuss why food plays an important role in Christie's novels, and how everyday plants can make the perfect undetected murder concoctions.

Alan Carr explores the life of the crime writer, meeting fellow fans including the Rev Richard Coles and going behind the scenes on The Mousetrap. He also visits locations including the remote yet stunning Burgh Island and Greenway House in Devon, which helped influence some of Agatha Christie's most successful novels.