Martin, not really thinking about what he was doing and not understanding the consequences of his actions, aimed Harry's "arrow" at someone on another floor of the building across the street, then locked onto them, altering them. At that moment, their pasts began to merge, so that they would have ended up together.
"Hey, it's still happening," a Cupid said. It turned and looked at Harry, seeing that he wasn't using his "arrow". In fact, he didn't have the "arrow" at all! The Cupid left his monitoring post and sought out a supervisor. Someone was using Harry's "arrow" and the timeline was again being irreversibly damaged because of it.
Harry looked around and saw that for the moment, he was alone. He wondered if he could use this opportunity to escape, go back to Earth, and find whoever took his "arrow", before the other Cupids got their hands on it.
Back on Earth, Martin realized too late that he had caused two people to fall in love with each other. But who was the 37-year old married woman's new lover? And how had the past changed to accommodate the relationship?