- Apocalypse How/Class X-5: The Tractites creating an alternate reality threatens to pull the Multiverse into the Time Vortex.
- Cold-Blooded Torture: What the Tractites do to the Doctor.
- The Dreaded: The Uncreator, who will one day return to wipe the Tractites of Paratractis out.
- Earth All Along: Paratractis. Slightly averted as the Doctor works out it's Earth quickly.
- The Empire: The Earth Empire.
- Genocide Dilemma: A major part of this story. If the Doctor restores history he will effectively be doing this to the Tractites. Slightly subverted in the end. Though he can't prevent the invasion he is able to give the survivors their freedom.
- The High Queen: The Earth Empress who agrees to grant Tractis independence.
- Humans Are Bastards: The humans attacked Tractis, killing or enslaving many of the natives.
- Kill All Humans: What the Tractites want to do.
- A Load of Bull: The Tractites look part-ox.
- Make Wrong What Once Went Right: The Tractite plan to wipe out humanity. However it poses a big Moral Dilemma for Sam as she sees how good the world is under them and hears how the humans attacked them.
- Nice Job Breaking It, Hero: Sam letting Kitig into the TARDIS almost gets the Doctor killed.
- The Plague: How a Tractite left in the present and Jacob try to wipe out humanity.
- The Slow Path: The TARDIS has to take this through 1.07 million years when it is thrown into a volcano.
- Timey-Wimey Ball: Very much so. A timeline that shouldn't exist, being foiled by a Stable Time Loop.
- Write Back to the Future: On the Doctor's instructions Kitig leaves these to tell Sam and Jo to find the TARDIS. After the Tractites are stopped he spends nearly all the rest of his life making the messages to make sure they are found.
Recap / Eighth Doctor Adventures Genocide
The Doctor and Sam travel to 2108 and find that Earth is now Paratractis, a Tractite colony. The Doctor realises history has been changed. Jo Grant gets caught up in this as well.