The 16th series sees the fourth Doctor (Tom Baker) joined by the beautiful Romana (Mary Tamm) in this 26-episode intergalactic treasure hunt for the all-powerful Key to Time. The entire sixteenth season of this BBC classic featuring six linked stories from 1978. Tom Baker, the popular fourth Doctor, is joined by the beautiful Romana (Mary Tamm), dispatched by the White Guardian to recover the Key of Time before the evil Black Guardian can inflict intergalactic mayhem. Packed with DVD extras.