Answer:
It is unexpected that the bachelor becomes involved with the family and storytelling.
Step-by-step explanation:
"The storyteller" is a short story by H. H. Munro, known as Saki.
The story revolves around three curious children constantly asking their aunt numerous question while travelling in a railway carriage. In order to keep them quiet, she decides to tell them a story, only to be confronted by an unknown man, a stranger, riding the carriage with them, about her obvious lack of story-telling skill. The stranger then proceeds to tell them his version of the aunt's story.
Since the man was a complete stranger, we could say it was rather unexpected of him to become involved with the storytelling so suddenly.