The Passing of Mr. Quinn

The Passing of Mr. Quin is a 1928 British mystery film which was codirected by Leslie S. Hiscott and Julius Hagen, starring Clifford Heatherley, Mary Brough and Ursula Jeans. The film was based on the short story The Coming of Mr. Quin, part of the collection The Mysterious Mr. Quin, which was written by Agatha Christie. It was the first British film to be made of one of Christies works. The short story was adapted by Hiscott, who would in 1931 direct Alibi, the first film to feature Christies more well known Belgian detective Hercule Poirot. The film was made at Twickenham Studios in London.

Professor Appleby has terrorised his wife, Eleanor, but when he is murdered, and her lover, Derek goes missing, Eleanor suspects the worst. A mysterious stranger, known as Mr Quinny or Mr Quin appears, and begins to seduce Eleanor, but his alcoholism takes over and he dies. Before dying, he reveals that he was Derek all along, and offers the girl to a rival, who promises to make Eleanor a happy wife.

Source: Wikipedia