The Professor's Mystery

Young Professor Crosby planned to spend the summer abroad. Having missed his boat to Europe, he gets on a train and meets a young lady he had met once earlier at a party. While on the train, they discover they are attracted to each other but don't admit it. On the way, there's an accident, leaving the girl a bit shaken. He offers to take her to her house, where he is invited to spend the night as it is already late. But the mystery starts when he is asked to leave without reason. Why was he asked to leave suddenly? What secret does the household seem to be hiding?