Urgent Calls ( audio story ) Urgent Calls was the part of the ninety - fourth monthly " Doctor Who " audio release produced by Big Finish Productions . It is the first single part story included with a three part story and the first solo Sixth Doctor story that was part of the monthly series since " Davros " in 2003 . This story began a story arc which concluded two years later , in " Patient Zero " . On 27 May 2013 , it was released for free on Big Finish ' s Sound Cloud page . Publisher ' s summary . Earth , 1974 . An innocent phone call . Okay , it was a wrong number , but there can ' t be any harm in that . Can there ? Plot . In an attempt to call her mother for advice , a deeply concerned Lauren Hudson ends up phoning a man who calls himself the Doctor . He informs her that she has the wrong number , but assuming that he is a doctor of medicine , Lauren informs him of her concerns ; the one which intrigues the Doctor being that the skin around her fingernails is broken and bleeding . He insists that she is seen to at a hospital straight away and be as persistent as possible to get a check up , specifically on her neck . Lauren agrees with his advice and hangs up . A couple of weeks later , Lauren is at her job as a telephone operator and ends up calling the Doctor again by another wrong number . She tells her story ; after insisting that she got seen to at the hospital ( even putting on a show of crying ) , she was attended by doctors who increased in numbers as they noted something strange about her neck . After being quarantined for a couple of hours , an Army Official and a specialist doctor attended her , the latter of whom informed her that he was going to operate on her . After the operation , he showed her what they had found - a 6 inch - long parasitical metal worm that had been clinging onto her spine , which would have killed her within a day had she not had the operation . The Army Official had made her sign the Official Secrets Act to declare that she would not tell anyone of this event , but this had made her feel isolated in the weeks since and thus she was incredibly satisfied to finally be telling someone about it . She asks the Doctor how he knew what was wrong with her just from the information about the fingernails , to which he replies " Experience " . She also asks if it was alien , which the Doctor confirms . Lauren explains how she thought about thanking him so often and how glad she is to get the opportunity to finally do so , although the Doctor notes how suspiciously coincidental it was that she managed to reach him through a wrong number twice . An abrupt disturbance on his end of the line results in him having to rush a goodbye , which Lauren is disheartened at . When trying to ring her friend Connie , Lauren once again gets in contact with the Doctor again through yet another wrong number . The Doctor explains how this is not merely a coincidence ; the first time she had called him she was desperately seeking medical advice , and the second time she had been thinking about thanking him . It is in actual fact a virus , a theory he was able to confirm when he noted that he got wrong numbers after each time he tried to call someone after his previous conversations with Lauren , yet the people he ended up calling become very useful in helping to defeat other not - so - lucky people who had died from the worm parasite which Lauren had and turned into slug creatures . The virus in the phone causes people to make subconscious mistakes when they next use a telephone , yet the person which they end up calling is someone they can help or vise versa who then gets the virus and passes it on until it reaches the end of its lifespan . Lauren asks how this supposedly alien virus ended up on Earth to which the Doctor says he ' s working it out and hoping that it only ended up here by accident . He asks a favour of her ; to make a note of every wrong number she makes from now on and who they are - this will be helpful in tracking the virus back to its original source . Lauren asks if he wants her number , to which the Doctor assures her that , thanks to the virus , they may certainly talk again .