In 2084AD The Doctor, Tegan and Turlough land on Sea Base 4 just as it comes under attack from the Silurians and Sea Devils; the original owner and masters of the planet Earth. With the threat of a nucleaer conflict that could wipe out the planet; will The Doctor be able to make peace between humanity and the prehistoric reptile; or will he have to revert to another way to save the Earth. Cast Peter Davison (The Doctor), Tom Adams (Vorshak), Nigel Humphreys (Bulic), Ian McCul