Christopher has not heard anything about Serena after their property has been sequestered and also had no idea where she was. Even then, he was curious, but not interested enough to find out. But when he saw Leonard's impending case, his curiosity was reignited. Would she be out of hiding once this case was delivered?
It was only a few days after when someone he didn't expect came along. Emily. His ex-lover who was also the only other person in the ton who knew that he was interested in Serena.
He was not sure of Emily's reason until she mentioned Leonard. Apparently, they were in a relationship. He didn't know about that detail until that moment. She asked for his help.
In truth, he could have helped her given their past and her being quiet about the matter of Serena, but then something, rather someone came to mind. If Emily was with Leonard, then what were the chances that Serena was with them?