Story 80 - Terror of the Zygons

In which the Doctor and his companions return to Earth at the behest of the Brigadier - the TARDIS materialising in the Highlands of Scotland. They are given a lift by the Duke of Forgill - the local laird - to the nearby village of Tullock, where UNIT have set up a temporary HQ in the hotel. The Brigadier informs them that a number of North Sea oil rigs have recently been destroyed - suddenly and completely. The Doctor is at first indignant that he has been brought back to Earth because of Mankind's over-reliance on fossil fuels, but soon becomes intrigued. One piece of wreckage has what appears to be the indentation of a massive tooth. He notes Tullock's proximity to Loch Ness. Harry finds a survivor of the most recent tragedy washed up on a nearby beach. The man is shot dead by a sniper, and Harry wounded. He is later abducted from the oil company's sick-bay.

At the bottom of the Loch lies a Zygon spaceship. It crash-landed here centuries ago. The Zygons released a Skarasen into the loch - a huge cyborg reptile - and its rare appearances on the surface have given rise to the stories of "Nessie", the Loch Ness Monster. The creature provides lactic fluid upon which the aliens thrive. The Doctor finds a partly organic homing device attached to another piece of wreckage, and deduces that it is placed there to attract the Skarasen. The rigs are in the creature's path to its North Sea feeding grounds. Zygons are able to disguise themselves as humans, provided they have the original person to provide a body-print. A duplicate of Harry is sent to retrieve the homing device. Sarah recognises that it is not him due to the lack of emotions. The creature is killed and the body disintegrates. The homing device sticks to the Doctor's hand, and he is almost killed by the Skarasen as it passes the village - the inhabitants having been gassed and temporarily put to sleep.

A tunnel is discovered between Forgill Castle and the alien spaceship. Sarah enters it and rescues Harry. The Doctor is captured. He learns from Broton, the Zygon leader, that their homeworld has been destroyed. They have sent a message to their fleet to come to Earth. Broton plans to have conquered the planet and terra-formed it to make it more suitable for his people. The fleet will take hundreds of years to arrive. The ship takes off when the Brigadier tries to depth-charge it. It heads south and, soon after, a large underwater object is spotted travelling down the North Sea. The ship lands outside London and Broton - in the guise of the Duke - departs for the city. The Doctor escapes and uses the radio system to broadcast their location to UNIT. He frees the real Duke, along with his ghillie and the oil company nurse, then sets the self-destruct system. The craft is destroyed. The Duke is head of the Scottish Energy Commission and is due to take part in an important conference at a Thames-side building. They realise Broton plans to destroy it using the Skarasen. He is killed by the Brigadier, and the Doctor throws the homing device to the Skarasen as it emerges from the river. It swims back to its home in the loch. Harry elects to remain behind, but Sarah accepts one more lift in the TARDIS.

This four part story was written by Robert Banks Stewart, and was broadcast between 30th August and 20th September, 1975. It marks the beginning of Season 13, but brings to an end a sequence of interconnected stories begun with the conclusion to Robot the year before. The story had originally been intended to close the previous season, which does seem to be where it should naturally fit.
This season sees Hinchcliffe and Holmes really get into their stride, no longer saddled with stories commissioned by the previous production team.
Whilst Robert Holmes wanted to retain Harry, in order to provide more sub-plot opportunities, Hinchcliffe felt he was surplus to requirements - and wanted the relationship between Tom and Lis built up - so had him written out. Ian Marter would make one further appearance in the programme - in a story directed by his creator (The Android Invasion).
The story would also prove to be Nicholas Courtney's last regular appearance as the Brigadier, as UNIT was being phased out.
Doctor Who had occasionally taken existing legends and given them a Sci-Fi spin - the Yeti being an obvious example. The idea of a Doctor Who explanation for the Loch Ness Monster seemed too good to pass up. The Skarasen works in the sequences where it pursues the Doctor across the moors, but the glove-puppet version at the story's climax is the only real failing of this production.

The Zygons make for one of the best Doctor Who monsters ever seen in the programme. Not only a brilliantly grotesque design (James Acheson), but  they have a fully realised culture and a number of attributes which makes it so surprising they were never used again. John Woodnutt (previously Hibbert in Spearhead From Space and the Draconian Emperor in Frontier In Space) plays the double role of Broton and the Duke of Forgill. It is a remarkable performance. Other guest performances worth noting are Lillias Walker as Nurse Lamont - and her Zygon duplicate - and Angus Lennie (The Ice Warriors) as the hotel landlord who has second-sight - but doesn't see his own fate.
Though filmed in the Home Counties, the story certainly feels like it could have been shot in Scotland, helped immeasurably by the  talents of director Douglas Camfield and by Geoffrey Burgon's wonderful incidental score. It is one of the series' best.
Episode endings are:

1. Sarah is talking on the phone to the Doctor from the oil company sick bay. She turns round and is confronted by a Zygon.
2. Broton has sent the Skarasen to destroy the Doctor, who cannot get rid of the homing device. The Doctor runs across the moor and falls, as the creature towers over him...
3. The depth charge attack fails as the spider-like Zygon spaceship emerges from the loch and disappears into the sky...
4. Sarah is going to return to UNIT HQ in the TARDIS, but Harry will be travelling by more conventional means.

Overall, a near perfect story. A few stories just miss perfection because of the inclusion of one element - the rat in Talons, the Magma Beast in Caves, anything with Colin Baker's costume - and sadly the Skarasen's final appearance lets this down right at the end. Apart from that, one of the best stories ever. I'm really looking forward to the Zygons' imminent return. Long overdue.
Things you might like to know:

• We know that the Zygons will feature prominently in the 50th Anniversary story - hopefully heralding a story of their own in Series 8 or 9. Steven Moffat has signposted their potential return a couple of times. They're mentioned - but not seen - as part of the Pandorica Alliance; and the Doctor's anniversary gift to Amy and Rory of a stay at the Savoy Hotel is marred by the fact that the hotel has been infiltrated by Zygon duplicates (The Power of Three).
• A Zygon was supposed to have appeared amongst the prisoners in Shada.
• Famously, this story prefigures Britain's first female Prime Minister. Nicholas Courtney ad-libbed that he was talking to a woman PM. Of course, it wasn't intended to be Mrs T. The PM in The Green Death had been Jeremy (possibly Liberal leader Jeremy Thorpe) and the female PM in this was probably intended to be Shirley Williams.
• The second release for the VHS (the episodic one) featured an alternative prequel. The Doctor is at the cinema when he gets the message from the Brigadier (Tom Baker having presented the popular Disney Time just before this story was broadcast) instead of the message coming through at the end of Revenge of the Cybermen.
• A deleted scene is to be included in the forthcoming DVD release - featuring the TARDIS' arrival.
• It is implied that the Zygons are a very long-lived race. The earliest instance of the Loch Ness Monster being sighted is in a story regarding Saint Columba in 565 AD. He chased off a "water serpent" in the River Ness.
• Some people don't believe in the Loch Ness Monster. Probably the same people that think Elvis is dead.
• Never underestimate the power of organic crystalography.