Martin challenges Zoe as to whether Greg is a man who is flailing and innocent, or guilty and acting innocent. Martin begins to identify with the isolated Greg and is increasingly torn between whether he is watching a guilty or a desperate man. Whilst Greg leads the surveillance team to a startling discovery, Martin’s guilt over leaving his post in episode one is now compounded when he is asked to formally ID the woman who broke into Greg’s flat. His friendship with Zoe blossoms as he supports a fractious Caitlin, distraught that her favourite teacher is still missing. Whilst Martin reveals surprising information about Gemma, Greg makes an unexpected move, catching the attention of DCI Conroy. And when Martin witnesses a shocking incident, he looks at another resident of Westbury Street in a whole new light.