The real backstory is that when Robert Smith was 10 he crashed his bike and suffered from a pretty big concussion. Due to the severe crash, he saw visions/hallucinations of a girl he called "Bunny". This would go on for 2 years. The hallucinations about this girl finally stopped, age 12, when a plane he was on hit bad turbulence causing a very nauseating painful headache. Coincidencely, afterwards he meets a girl at the airport who was "a spitting image of Bunny", the girl's name was Anna. This song is about pretty much a once-in-a-lifetime "chance meeting", and honestly that's pretty cool