Over time Mark quit asking about Sarah. No one knew where she was or if she was coming back. Mark realized that asking Agnus for updates about Sarah only upset her, so he stopped asking altogether. Mark spent the little time he wasn't in the library with Charles learning self-defense. Mark and Charles had become good friends. Mark found that he considered Charles a closer friend than anyone from his office. He had spent nearly twenty years at that office and didn't have one real friend except for Sarah.
Mark missed Sarah. He found that when he wasn't in the library, and he wasn't with Charles, all he did was think about Jen, Katie, and Sarah. How had Sarah become so important to him? She was his sister-in-law, but somehow she was a lot more. She had been his best friend for most of his adult life, but there was more to it than that.