Doctor Who fan fiction.
'Changeling' blends together the events of the first Doctor Who serial, 1963's 'An Unearthly Child', and 1988's 'Remembrance of the Daleks', which reprised some of the events and settings of the 1963 setting (namely, Coal Hill School and the Totter's Lane junkyard).
'Changeling' combines two of the Doctor's companions, Barbara Wright and Ian Chesterton (now married, with a young daughter) from the 1963 serial, and the unnamed girl who was the focus for Dalek power in the 1988 serial, bringing them into direct conflict, as some of the few people on Earth who know of the Doctor and have been changed (or damaged) by his passing.