Forgetting Vivian Young {A Doctor Who Story}

Vivian Young has been travelling with the Doctor for seven months now and things are looking perfect. She's got a key to the TARDIS and everyday is a new adventure. When the Doctor takes her to Germany her life takes a rapid turn. Instead of lederhosen, they found an abandoned house with an old woman inside holding a key in her hand. Something doesn't seem right so they leave quickly. The Doctor seems to be acting a little strangely and Vivian suddenly realises that not everything lasts forever. Not even memories.