Houdini and the Space Cuckoos, parts 1 and 2 (of Four) Joseph Lidster, 2012. Adventure Calendar short story.
Part 1: http://downloads.bbc.co.uk/tv/isite-downloads/doctorwho/masks_and_makes/stories/christmas-2012/Houdini-and-The-Space-Cuckoos-Part-One.pdf
Part 2: http://downloads.bbc.co.uk/tv/isite-downloads/doctorwho/masks_and_makes/stories/christmas-2012/HTSC/Houdini-and-The-Space-Cuckoos-Part-Two.pdf
