He followed her for hours
The puzzle
A man followed a woman he had never met for three hours.
She never noticed.
See the answer (spoiler)
Spoilers from here on. If you want to work it out yourself, leave this folded and move on.
Answer
They were both running the same marathon.
They happened to keep the same pace, so he spent three hours behind her.
She had headphones in and never looked round.
