The Deep Cover Agent appears to be a normal, happy, patriotic, stereotypical housewife and/or soccer mom. In reality, though, she (and it's always a she) is actually a spy working for the Soviets. Or, at least, that's how the trope goes.
They are also known as Sleeper Agents. The idea is that the agent infiltrates the enemy country, and then keeps their nose clean for a very long time. During this "sleeping" phase, they don't report in, engage in espionage, or do anything that would arouse suspicion. They do, however, keep their eyes open for the prearranged signal that would reactivate them. There is also a chance that they might manage to penetrate the government or society of the targeted nation enough to become an Agent of Influence.
While operating under Deep Cover, the agent is of course not being paid by their sponsoring government, as that would leave a paper trail that might be noticed. They'll need to secure an income. This may mean they take a job in a sector (such as finance, politics, or science) where they can later (once activated) wreak havoc. Or, it may mean they initiate a romance with a person in such a job, so as to be able to spy on or manipulate such a person. One significant difficulty with inserting a Deep Cover Agent is that you don't know decades in advance who's a proper target, or what sort of businesses or agencies are worth infiltrating.
To help allay suspicions, Sleeper Agents are often natural born citizens of the country they are now "sleeping" in. At some point early in life, perhaps on a trip overseas, they were recruited by the other government. There's a strong element of faith involved here - you're recruited on ideological principles, and might never be activated or paid. As such, one imagines that Deep Cover Agents are probably relatively rare, or a bad career move, or both. Despite that analysis, Deep Cover Agents have (and probably still do) existed, with several having been planted shortly after World War I. Otto Kuhn was installed by the Germans into Hawaii. Kim Philby was a Russian agent that infiltrated British Secret Intelligence Service. Both were activated during World War II.
Sleeper agents are most easily recruited when the opposed nations have extremely different ideologies (Capitalism vs Communism, Democracy vs Theocracy, etc). Oppressed minorities are a possibility, as well. If the two factions involved are very similar, there's probably not a lot of motivation for betraying the country of your birth for a long slow job that doesn't pay unless you're eventually activated and later defect.
Lastly, it's worth reiterating that in the real world, the Deep Cover Agent could be of either gender, and isn't necessarily a housewife.
Game and Story Use
- There's at least two ways to run a campaign with a Deep Cover Agent as a PC:
- This would probably work well for a solo campaign in the espionage genre. The PC might be married to an enemy agent, politician, or scientist, and secretly reporting back to the motherland. There's a high likelihood that the cover will eventually be blown, which would require a pretty big shift to the fundamental dynamics and paradigms of the campaign.
- Or, if the GM fights dirty and one of the players is willing to oblige them, you could have one PC be a sleeper agent within the party. They work with the rest of the party for the first 6 sessions or so, and then get activated by the enemy.
- One benefit of the Deep Cover Agent NPC is that there's no paper trail, no money trail. You can have any NPC turn out to be "the bad guy" without any clues or signals to tip off the players. Just don't over do it.
- Why do some players never create PCs with any family connections? Because any family member is either put in jeopardy, or is secretly plotting against you. This one's the latter. Realize that if you use a Sleeper Agent NPC, you may be encouraging the players to make their next character a loner and an orphan.