10 Star Trek Production Secrets Behind These Cliffhangers

10. The Adversary

The Adversary is a strong season finale even though it was a last minute re-write to close Deep Space Nine's third season. The Changeling that infiltrates the USS Defiant warns Odo that his people have already invaded the Alpha Quadrant and no one knew a thing about it.

It is a chilling moment in the show and a dark ending to the third season. The writers, though they hadn't planned on it, ended up crafting the perfect note to leave audiences on.

Paramount Pictures had nixed the idea of having Homefront and Paradise Lost being the bridge between the third and fourth seasons, though the idea of Changelings on Earth is present in all three stories. It is touched on in The Way of the Warrior, with Martok demanding blood screenings before his meeting with Sisko and Kira.

There is also a hint of John Carpenter's The Thing on show while the crew conduct their blood texts in the mess hall of the Defiant. The entire episode is a triumph, capturing the paranoia and tension that Homefront and Paradise Lost, unfortunately, would fail to manage in the middle of the next season.