This was an idea I was noodling with:
Every year, thousands of sentient beings across the Federation apply to Starfleet Academy. Some dream of commanding a starship on a mission of exploration. Some hope to push the envelope of technology and engineering. Some seek to further our understanding of the universe through scientific discovery.
And then, once in a while, there are others.
They are the ones that know that even though the Dominion War is over, the Federation still has enemies. They are the ones who take nothing at face value. They are the ones who know that infiltration and deception can be as potent a weapon as any phaser. They are the ones who know a key piece of information can save (or destroy) a civilization.
These are the officers of Starfleet Intelligence.
Under the guidance of Commander Chadwick, the newest members of Starfleet's most mysterious branch will learn to pass themselves off convincingly as various alien species, gain the trust of those who trust no one, and face ethical dilemmas most officers cannot imagine, all in the name of protecting the Federation.
The work is dangerous, often sending operatives into the heart of regimes where the Federation is despised, and being discovered as a spy means a slow, painful death.
Yet these areren't the only risks they face: An operative more willing than most to bend the rules and compromise principles may find themselves approached by a rogue section of Starfleet always on the lookout for such individuals to join their cause, and whlie these latest recruits may all share a dedication to protecting the Federation, their differing methods mean they won't all be on the same side...