In 2007, Max Klein, an East German immigrant, bled to death. His mysterious last words were "blue flower". Piecing together his story, the team learns that Klein once had connections with the Stasi, East Germany"s dreaded secret police. But did he work for them or against them?

Someone has just tried to kill Stephen Fisher, and Strickland may be next. Thirty years earlier, both were part of a group involved in a covert operatioon for MI-5. Other members of the group are already dead, Stricklad turns to Sandra ad her team for help