We watch "The Unicorn and the Wasp" (Series 4, Episode 7) where the Doctor and Donna travel back to the 1920's to play a live-action game of "Clue". Arriving at an English country manor, the Doctor plays "Watson" to Agatha Christie's "Poirot" and the WASPy Reverend Golightly turns all Waspy driving Donna on an all out bug hunt. All whilst the British upper crust enact a wacky pantomime involving bastard children, "confirmed" bachelors and a non-magical Unicorn.