Silent Partner was a Kaldor City audio story written by Jonathan Blum. It acted as a prequel and a sequel to both Kaldor City and The Robots of Death, centring on Poul, who is tasked by Landerchild to protect his daughter (Vydia) from a serial killer. Ultimately it is revealed that Vydia and her friends were manipulated into killing each other by Psi-V9, a psychiatric Voc that was treating them. The play also shows the first meeting of Poul and D84 and features Taren Capel and Cotton.
When Blum came to write the full script the story began to collapse, as elements crucial to the story began to contradict the direction the Kaldor City series was taking as a whole. Kate Orman tried to help rescue the script, but it ultimately was abandoned. (REF: Downtime – The Lost Years of Doctor Who)