Guinevere's Revenge

Downton Abbey meets It Happened One Night in this 1920s romantic mystery romp.

American silent film actress Stella Hart has been terribly fond of her English "step-cousin" George ever since his uncle, Lord Barrington, married her mom. She's a lot less fond of Mavis, his grotesquely snobbish fiancée. But when the lovesick gangster that Stella fled Hollywood to escape tracks her down at Barrington Hall, George pretends to be engaged to Stella to put him off the scent, and Mavis, poor girl, plays along. 

Then Stella and Mavis find a dead man in the woods, and things get really exciting. The only likely witness to the murder is Guinevere, Mavis's fuzzy little Bichon Frise. 

And Stella's best suspect is George.