Two schoolteachers, Ian Chesterton and Barbara Wright, become concerned by the unusual behavior of their fifteen-year-old student, Susan Foreman. When they follow her home, they meet her mysterious grandfather, the Doctor, and find themselves unwilling passengers on his time ship. The first episode deals with Ian and Barbara's discovery of the Doctor and the TARDIS in a junkyard in contemporary London. The following three episodes are set amid a power struggle between warring Stone Age factions.
Source : 'An Unearthly Child' - Wikipedia entry http://en.wikipedia.org/wiki/An_Unearthly_Child (Sighted 4/05/10)