STORY PLOTLINE
The TARDIS lands on the surface of the sea, just off the east coast of England. The time travellers use a rubber dinghy to get ashore, where they are shot with tranquiliser darts and taken prisoner by security guards as they have arrived in the restricted area of a gas refinery.
At the refinery base, run by a man named Robson, the Doctor learns that there have been a number of unexplained problems with the pressure in the feed pipes from the offshore drilling rigs.
COMMENT Spoliers ahead