Episode 130 - Warriors of the Deep

In the near distant future, humanity is engaged in another cold
war. Far below on the ocean floor, a base belonging to one of the
factions stands poised for war. This week, Paddy and Tricia
follow The Doctor and his companions as they arrive at the base
as tensions heighten at the arrival of a mysterious battleship.
However, it is much worse than anyone realizes as The Doctor
recognizes these Warriors of the Deep.