In episode 4 of ‘Spearhead from Space’ we see the Autons bring their plan to its climax, an all out attack on Britain. This gives us one of the most memorable scenes of the series, shop dummies coming to life and gunning people down in the street. The location shooting on film only serves to heighten the realism and terror.
The overall plot of ‘Spearhead from Space’ can be best described as a secret invasion. Rather than announcing their presence at the same time as their initial attack they first establish themselves in the place they are invading, so that they can weaken their targets defences before the first strike.
Secret invasions proceed along the follow steps:
Step 1: Arrival
The invading force must first send agents to the location to be invaded without being detected. In this story this is done by sending waves of meteors containing the consciousness of the Nestenes.
These agents must establish bases of operation and lay the ground work for the following steps. It is at this point that the invaders plan is most vulnerable. They have few numbers and resources. The advantage is that their smaller numbers mean it is harder for them to be detected.
Step 2: Infiltration and Intelligence Gathering
The invaders must gather any tactical information that they weren’t able to gather before. For alien invaders there is a lot to understand about the culture they plan to invade but they will be concentrating on learning what offensive and defensive capabilities their targets have.
This step is best achieved by agents who can pass as human. In this story we can see that Channing was likely responsible for much of the operations in the UK, including seizing control of the plastic factory.
Invaders might be shape changers or able to to take over their targets minds. Covert activity always brings risks and there is a danger that if they are caught their true origins might be revealed, putting the plan at risk.
This can be a very effective step if the invader is able to assume the identity of a real person. It gives them a ready made back story and even provides them will a degree of power if they have taken the place of an important figure.
To make up for their small number agents may enlist the services of others, as Channing does with the owner of the factory Hibbert. The more people involved the greater the chance that information about the operation might be reveal. Agents will need to be careful what they tell those working for them.
There are many stories, both in real life and in fiction, of infiltrators finding their loyalties changing as they get to know the culture they are infiltrating. This will depend entirely on the type of agent employed for the task.
Step 3: Entrenchment
Once agents are part of the society they plan to invade and know where to strike they must build up their power base. This could involve smuggling in more agents or stock piling resources that will be required for the coming invasion.
The plastic factory is ideal for the invading Nestene. It is established base of operations, has all the equipment they need to produce more Autons and even a distribution system that they can use to put these soldiers into position.
The risk increases when obvious offensive resources are stockpiled in a single location. Any one keeping an eye on the movement of dangerous items, such as weapons or certain chemicals, might start to ask questions about why such large quantities are being sent to a single location.
Disguising the resources or smuggling them is the answer to this. No one would be concerned about large quantities of shop dummies stored a plastic factory. As long as no one discovers their true nature no questions will be asked.
During the entrenchment phase a strong defensive position much be established. When the invasion begins the invaders will need to be able to repulse attackers in order to continue operating.
Again this preparation must be done covertly. All attempts as secrecy will be ruined if their base is turned into a fortress overnight. People will wonder why they are getting ready to defend themselves.
Step 4: Placement
This is the final stage before the invasion itself. Now that the necessary resources have been gathered they must be placed where they can best weaken their target. It is this phase which the whole secret invasion hinges on.
A secret invasion gives the invaders an advantage, gained by using the element of surprise to weaken defensives enough to allow the main force to invade. If they didn’t need this advantage there would be no point to the secrecy.
In this case it is the placement of the Autons in shops and using facsimiles to infiltrate the government and military. This seems to have been done to compensate for the relatively fewer Auton agents they have compared to the size of the British army.
This is a very delicate stage as if the target would leave the countries defences weakened they will usually be protected. Putting resources in place to damage them must be done in such a way to avoid the placement being detected.
Once the resources are put in place they can be activated, signalling the commencement of the invasion.
Step 5: Invasion
This is what it has all been leading to. Using the chaos the main body of the invasion force strikes, exploiting any weaknesses they can find.
Structurally an adventure can begin at any stage of the secret invasion. They could become involved during the initial arrival of the invading force, find an infiltrator during the second step, or even come in right at the end as they become aware of the placement of resources and realise how vulnerable they are.
Just being aware of a secret invasion is not enough to stop it. The Doctor gives UNIT enough warning about the coming attack but even knowing that it will happen they don’t know how and so are unprepared when people starting being killed in the street.
Once they do know about the plan they must hunt those involved, gather information about the plan and find a way to prevent it. The quicker they are at doing this the more trouble they can avoid down the road.
Such adventures can be used to bring a little espionage to your game in the vein of James Bond or 24. Knowing that the invaders could be anyone can make player characters suspect everyone and the fact that a large scale invasion will occur if the player characters fail certainly provides a lot of tension.
In ‘Spearhead from Space’ the Doctor uses the information he has gained so far to create weapon that shuts down the Autons, a good example of the Boffin trait and Jiggery-Pokery rules being put into practice.
In general this is a good guide to how the climax of the adventure should play out. The player characters should have gained something through the course of the game, whether it be knowledge of the enemy or the tools they need to defeat them, that allow them to win.
If the player characters didn’t gain anything during the game then that time wasn’t well spent. You could have simply started the game at the end and they would still have succeeded.
It is that growth and development that makes an adventure worthwhile.
Bigger On The Inside 
Nice. Linked back to. 🙂