Fan Casting Doctor Who Season 28 (1991)

Taking Katie into the mansion after she fell into a lake, the trio witnessed a series of deaths amongst the academics that were living there and discovered that they were experimenting with time, with a device they called the Bartholomew Transactor, so they could send a message back in time to their past selves about misdiagnosing a deceased girl known as Eddie O'Neil. However the interference with the timeline caused Eddie to transform into a zombie-like state of limbo, the Doctor realised that the misdiagnosis had never been genuine and that the whole series of events were part of a cruel time experiment conducted by Major Dickens, who intended to correct the academics' mistake. The Doctor traveled back in time to undo the damage, but found himself unable to kill the child, allowing the zombie Eddie to come into existence . Returning to the present, the Doctor discovered that all the academics were now deceased, and theorising that the Zombie-Eddie was responsible for the deaths, keeping herself “Alive” through her own use of the Transactor. He, Katie and Henrick departed.