TNG - "Q Who"

Q returns, whisking away the Enterprise to a sector of space where they encounter the Borg, a nigh-omnipotent cybernetic race. After the Enterprise is helpless to defend themselves against the Borg, Q returns the Enterprise home with the knowledge that the Borg are now aware of the Federation, and will be coming for them in the future.

This is one hell of an episode.

First of all (and somewhat unrelated to the main plot), we get a ton of information about certain incredibly powerful beings. Q states that although he still retains all of his powers, he has been "kicked out" of the Q continuum. That's certainly a fascinating idea. What's even better, Guinan and Q have a magic-hands face-off!

It doesn't really lead anywhere, but it's funny. Q refers to Guinan as "an imp," someone who's dangerous to the Enterprise. Does this mean that Guinan has abilities on the level of Q? She certainly has a certain knowledge of the Q, as well as other alien races in this unknown sector of space. Speaking of which, this sector, though not terribly far away from the Federation, is basically the edge of what we'll come to know in Star Trek Voyager as the Delta Quadrant. Q states that it contains "wonders more incredible than you can possibly imagine, and terrors to freeze your soul." No more little insignificant planets where the greatest threat is that they might blow themselves up if they got their hands on a phaser because they're too stupid; now we're dealing with races so far beyond the Federation's level that they can't even run.

After this, it feels as though the entire show has been changed. There's no more lounging about in the flying leather sofa that is the Enterprise-D, casually dealing out space justice. Now there's a looming threat that defies the humanistic "we are above all" ideals of the Federation as well as the notion of general safety. Much as in "Skin of Evil," The Enterprise can do nothing more than simply run (and in this case, needing Q's help to do so), taking a heavy loss. Unlike "Skin of Evil"'s Armus, however, the Ent-D crew can't simply run away and forget this encounter; this time the threat will follow them. No one "important" died here; we're just given a simple mention of the fact that eighteen crewmembers were killed when the Borg sliced up the Enterprise's saucer section. But somehow this feels far more chilling than anything we've seen before. And from a purely statistical standpoint, 18 crewmembers is an absolutely huge loss, considering that the Enterprise-D has rarely lost anyone in its journey thus far, and never more than one or two people at a time.

The Borg are the exact inverse of the Federation. If the Federation's greatest strength is its ability to solve problems through peaceful negotiation, then the Borg are invincible against them. Though we really only get a preview of them here, the Borg have the potential to become the biggest and best villains in Trek history.

This episode might be the best in the series thus far. It's just a taste of what's to come, but it's a powerful one.