Well, walking plant monsters. Yeah, I’ve probably seen them before, but here they are now.
This kind seems to be the sort that just kills everybody just because.
But first, to avoid the black hole, we find out why the head of security couldn’t find the killer.
He was doing something else. Flooding the bridge with toxic marsh gas and sending in two aliens who wear gas masks anyway, he takes over the ship, intending to sell it or something. Mel and two others manage to escape, but then someone else kills the gas mask guys, and without them, the security chief surrenders pretty quick.
Meanwhile, the Vervoids are killing anyone they come across, including the plant-woman hybrid.
At any rate, the Doctor figures out who the killer is, what the Vervoids are, and so forth. The Vervoids are a new species one of Lasky’s associates was bringing to Earth as cheap slave labor. And Lasky more or less created the things. So, this being Doctor Who, the Vervoids conveniently kill off the security chief, the killer, and Lasky, and the latter two both tried individually to befriend them. Don’t shake hands with a killer plant monster.
So, will the Doctor be able to save the ship? Can he find a weedkiller?
Nah! He knows about some element that speeds up plant life, and with that, and Mel’s screaming (seriously, she’s either screaming or being way too helpful for a character we’ve just met), the Doctor manages to wipe out the Vervoids, something he didn’t necessarily try to do, but he knew these things if they got to Earth would kill every human being without too much trouble. So, he and Mel go back to the TARDIS, and the Commodore running the ship hopes he doesn’t see the Doctor again for a while since the Doctor always brings trouble.
And, back at his trial, the Valeyard decides to up the charges against the Doctor to genocide.
This just got a whole lot worse for him. He better tie all this up in the next two episodes. It’s all the Sixth Doctor has left.