'Warriors of the Deep' (4 Parts) Story Code '6L' by Johnny Byrne

The TARDIS arrives inside Sea Base 4, an undersea military base, on Earth in 2084, a time when the planet is split into two power blocs. Initially, the base commander, Vorshak, mistakes the Doctor, Tegan and Turlough for enemy spies and saboteurs, but is forced to enlist their help when the base is attacked by a mysterious undersea craft, commanded by three Silurians. These Earth Reptiles, led by Ichthar, the surviving member of a Silurian Triad, unleash a giant vicious marine creature known as a Myrka, which breaks into the seabase to pave the way for a squadron of Sea Devils. The Silurians plan to launch the seabase's nuclear missiles in act that will provoke a nuclear war between the two superpowers, resulting in the destruction of all human life on the planet and leaving it free for the Silurians and Sea Devils to reclaim. The Doctor attempts to reason with the Silurians, suggesting a peaceful co-existence with the humans. But the Silurians refuse, and the Sea Devils and Myrka continue to wipe out the crew of the seabase. The Doctor uses an ultra-violet light projector to kill the Myrka, and then he and his companions pump hexachromite gas, which is harmful to marine life, through the ventilation system, killing the reptiles much to the Doctor's remorse.

Peter Davison (The Doctor), Janet Fielding (Tegan), Mark Strickson (Turlough), Tom Adams (Vorshak), Ingrid Pitt (Solow), Ian McCulloch (Nilson), Nigel Humphreys (Bulic), Martin Neil (Maddox), Tara Ward (Preston), Norman Comer (Ichtar), Nitza Saul (Lt Karina), Stuart Blake (Scibus), Vincent Brimble (Tarpok), Christopher Farries (Sauvix), James Coombes (Paroli)

Produced by John Nathan-Turner
Directed by Pennants Roberts

TX:
Part 1 - 5th January, 1984 @ 6.40pm - 7.05pm
Part 2 -6th January, 1984 @ 6.40pm - 7.05pm
Part 3 -12th January, 1984 @ 6.40pm - 7.05pm
Part 4 -13th January, 1984 @ 6.40pm - 7.05pm

Notes:
*Featuring the Fifth Doctor, Tegan, and Turlough