A taxi driver picks a girl up. He is driving. Unintentionally he looks at rearview mirror and he doesn't see anybody. Then I found this sentence:
おや? と思って振り返るとちゃんといるのです。
When I have read it I have understood that he is driving, he sees that nobody is there, he turns to the back seat but the girl is there. However, it doesn't make any sense to me. At the end of the story the author says that he was afraid but he continued to drive and when he stopped the girl was not there.
Can somebody explain this sentence to me?