This episode was totally about Canterbury and about her past. The previous episode already gave me a hint that something bad happened with her child. Now I learned that he was taken from a park while she was talking on the phone and looked away. This is the problem with her marriage.. and counseling does not seem to help it.
So, when a case just comes to her, she first believes that the man is innocent. Then it more and more starts to look like that man might be the one who took her son. But the truth is not so easy. The man is innocent as she thought first. Canterbury really believes he is a medium and takes him to the playground where her son was last seen, but he sees nothing.
But it looks like this is a potential future storyline...Really good one :)