The team reopen the murder of East German refugee Max Klein, whose last words were 'Blue Flower'. Visiting the site of his death Sandra and Steve meet Grace Cusack, whose son was killed at the same spot a year before Max's death and tells them he came to England to look for his daughter Mia who had escaped East Berlin ahead of him. Meanwhile Gerry and Brian visit a recycling centre where Max worked and learn that he stole bundles of documents but are challenged by arrogant Inspector Rosser, who claims that they could interfere with his investigation of the centre in connection with identity fraud. When Mia is located she denounces her father as a member of the Blue Flower group which was pro-Stasi though ultimately the deaths of Grace's son and Max prove to be related and less political than expected.