At this point I assume David Vincent just scours the newspapers for any report of a cerebral hemorrhage because when the aliens kill two guys in their usual way, of course Vincent comes to town to check it out. There he finds them doing their thing, he investigates, winds up on a saucer going into flight, and then lands somewhere else (it’s the Vasquez Rocks again). For a moment he isn’t sure if he’s still on Earth and neither is the viewer, which was neat. But he was on Earth, and he comes across a science class on a science hike or whatever. A teacher and five teenagers. Vincent tries to convince them there was a flying saucer nearby and it doesn’t go well.
Then we get a scene that I can’t help but find darkly amusing. Vincent and the teacher go off to explore the supposed aliens and they find a military base to sneak around in. They find what may be the biggest Invaders operation we’ve seen on the show so far, there’s like twenty of them around. Anyway, Vincent takes the opportunity to sneak in like a cheeky little guy and steal a piece of their technology, and it ends up getting the teacher killed. So then Vincent has to go back to the student and be like “Yeah, I went off with your teacher and he’s dead now, but you can trust me.” A very funny situation for our hero to be in (actual line of dialogue: “He’s dead. The people from the flying saucer killed him.”), though the Invaders make it easier on him by showing up posing as the real army and bringing the whole lot of them in.
What follows is the Invaders trying to get their crystal back from Vincent and the students, the students don’t know who to trust, various alien schemes, eventually the kids come around the Vincent’s side and win the day. Of course, when they bring in the real military to see the base, the Invaders have left no evidence of their operation there. A victory for Vincent and his allies (five of them survive this one!), but they can prove nothing. Typical fare, but not a bad episode.
The operation at the base, incidentally, was one we’ve seen before where they bring their people in to regenerate them. One Invader at the start of the episode (named Fletcher) is being brought there because he has chicken pox. That raises some questions for me. Is there something about their human forms that make them semi-susceptible to our diseases? If so, Vincent needs to look into biological warfare. The other question though is about why they’re bothering to heal Fletcher at all. We’ve seen these guys throw their lives away pretty casually (like the ones who killed themselves immediately after testifying against Vincent’s friend) so why is Fletcher worth saving? Was he a key part of some scheme? Alien stuff. Hard to get one’s head around.
The most important thing, though, is that one of the students is played by Dawn Wells! Another Gilligan’s Island actor! Between the previous one showing up in The Trial we’ve had the entirety of “The Rest” on the show.

