The Underwater War
Roots: Aliens (drop ships). There are references to Jules Verne’s 20,000 Leagues Under the Sea and Spongebob Squarepants.
Dialogue Disasters: “Tide and seek” and all of the Doctor’s other dreadful, water-based jokes.
Continuity: Hydron is purple and almost entirely covered in water, save for a few mountainous islands called Founts, which have fresh water pools at their summits. Marine animals on Hydron include rainbow-coloured jellyfish and large crab-like animals with ten legs. A Black-Trout is a power-drain creature that looks like an elephant-sized slug.
The Shoal is native to Hydron. Individual members of the Shoal are called Shoaly. They are marine creatures and communicate by changing colour. There are three species: the low swimmers are dark brown with grey stripes, big mouths, and strange golden eyes. Their “lure” is a small glowing ball between their eyes which can be used to hypnotise or electrocute. High swimmers are more humanoid, and medium swimmers are more colourful. Their front flippers have fingers. They can live in air for several hours. Their bodies carry a natural electric charge and their roe contains enough energy to power a starship. They hatch, almost fully grown, only a matter of days after their eggs are laid. Their eggs require laying in fresh water: they are incubated in the fresh water pools at the top of the Founts and return to the ocean via the Drops. Their capital city is called Reef and their towns are called Pools. The Shoal ride flying fish the size of airliners to reach the tops of the Founts.
MARVE is a Medical Assistance Robot Vehicle for use in Emergencies.
The Doctor is aiming for the Tower of London when the TARDIS materialises on board The Cosmic Rover. He claims to be from Health and Safety. He rigs up a translation device to communicate with the Shoal. His pockets contain a ball of string, a tangerine, a stick of chalk, a handful of paperclips and a sachet of tomato ketchup.
Amy and Rory don yellow overalls whilst on The Ocean Explorer. The Doctor and Amy later don orange diving suits. Rory wears a white quarantine suit in the medical bay. He later dons blue overalls and a climbing harness.
7D-24 is a poison. The planet Cartigan Nova has whirlpools of gold.
Links: The Doctor mentions Pescatons (The Pescatons), Sea Devils (The Sea Devils, Warriors of the Deep), the Skarasen (Terror of the Zygons), the Myrrka Warriors of the Deep), the Hath (The Doctor’s Daughter) and fish people and Atlantis (The Underwater Menace). Rory notes that he has been a Roman Soldier and a security guard (The Pandorica Opens/ The Big Bang). Amy recalls the Star Whale and Starship UK (The Beast Below) and the Silurians (The Hungry Earth/ Cold Blood).
Location: On board The Cosmic Rover and Hydron, the future.
The Bottom Line: Some excellent world-building, although it gets slightly unconvincing once we have submarines riding up waterfalls inside mountains. Still, very entertaining and surprisingly sophisticated considering the target audience.