The Fifth Doctor takes Nyssa to Vortis and has a stroll whilst the TARDIS works out some gravitational pull issue.He tells her he's only on a Busman's Holiday as the Zarbi come crawling out the woodworks, and rampaging for an unknown reason. They meet up with Acheron, a Menoptera, and his wingless daughter Hedyla, as they try and find out what's ailing the Zarbi, and who exactly was that mysterious stranger Nyssa saw in the Woods of Desolation?
- Abuse Mistake: This snippet:Nyssa: Doctor! The Zarbi are fighting them! Oh. Wait..The Doctor: Yes, erm, perhaps we should look away.
- Alien Sky: Several moons in the sky.
- Artificial Human: Both Xanthe and Yanesh are genetic constructs in humanoid form, created by mankind to, in a way, terraform a planet and spread out new life over barren ones.
- Big Creepy-Crawlies: The Zarbi and the Menoptera make another appearance.
- Bizarre Alien Biology: Acheron finds it peculiar that Nyssa and the Doctor only have to digest food once. He also instructs his daughter that she has to serve them non acidic drinks.
- Busman's Holiday: The Doctor claims that he doesn't go out looking for trouble.
- Call-Back: In combination with Sequel Episode, this heavily features the Zarbi.
- Nyssa mentions the trees of Vortis are very similar to those on Traken.
- Call a Rabbit a "Smeerp": The Zarbi, again, though the Doctor calls them more akin to termites rather than ants.
- Complaining About Rescues They Don't Like: The Doctor gets rescued by a Menoptera called Acheron before falling down a cliff, but this happens before he can grab Nyssa who slips out of his grasp.
- Continuity Nod: Acheron mentions when the Animus took over the Zarbi.
- The Corruption: The mysterious stranger that Nyssa saw later reveals himself to have some kind of a ... growth.
- "Eureka!" Moment: The Doctor has one when he's out with Hedyla, trying to find Yanesh.
- Half-Human Hybrid: The end result of this audio adventure.
- Have We Met Yet?: Nyssa asks the Doctor if they are here before the Doctor visited the planet before, but the Doctor manages to use the Alien Sky to deduce he isn't.
- Hive Mind: The Zarbi possess one, but can only express themselves through a speaker.
- Horse of a Different Color: The Doctor mounts a Zarbi at one point.
- The Professor: Acheron seems fascinated by the Web planet, and its wildlife, and alien visitors.
- Revenge Before Reason: As a swarm of Zarbi approach Menoptra cities, Nyssa has to talk Acheron out of not undertaking any action, because he should be better than that.
- The Swarm: The Zarbi swarm and ravage a part of the planet, but it takes so long that by the time they're done, the forest has recovered. There are thousands of them, at the very least.
