Roots: The idea of time travel shenanigans wiping out history has been done numerous times before. There are references to Greenpeace, Hershey bars, Snickers, and South Pacific.
Goofs: The Doctor's claim that the only bits of reality existing are two bits of Africa a million years apart makes very little sense. Fair enough that the first divergence point still exists, but why should the second point - whose existence depends on a particular outcome in the first timezone - still exist? Also, if there's nothing between them, how can the Doctor send a message from the earlier period to the later period?
Technobabble: The Universe is depicted as quasi-stable flux interference by the TARDIS. Chronon-wave asynchronous transmission. The Doctor's explanation on page 155 of why the divergent universe is causing major temporal trouble. Minerals on Tractis include Xantium and Cardinium.
Dialogue Disasters: The Doctor: 'Can you possibly help us? We seem to have mislaid our planet.'
Dialogue Triumphs: Jo's thoughts: 'First she'd saved the universe with the Doctor; then she'd saved the world with Cliff; now she was raising her son in a two-bedroomed flat in Hackney with two jobs and a bedroom that needed decorating and a roof that needed retiling and hadn't life been supposed to get better?'
Jo: 'This was freedom: to sit in your own kitchen, making a cup of your own cheap nasty tea.'
Jo 'wondered if she was walking into a trap. She'd always been good at that.'
The Doctor on Hynes: 'He wasn't responsible. He looked insane to me.'
Sam on Paratractis: 'It was still Earth, really, but it was still wild too - can you understand that?'
Jo: 'Maybe you just didn't recognise the alien corners.'
The Doctor: 'You're killing me because you're afraid.'
Mauvril: 'I'm not killing you. I'm going to have you executed.'
The Doctor: 'It's the same thing. It only means you're afraid of pulling the trigger yourself.'
'We all have to be Daleks sometimes. It's just a matter of knowing when you really don't have any choice.'
"How can information be permanent? Information is what people need in order to know about the world. The world is always changing, therefore the information has to change as well, or it's no longer information."
Continuity: The Doctor claims that the alternate timeline in which Earth becomes Paratractis causes so much instability that it could pull the entire multiverse into the Vortex.
Tractites are bipedal half-horse, half-ox-like creatures, with elongated snouts. They have three fingers on each hand and double-jointed arms. They have two pairs of eyes, one large pair on either side of the head, and two smaller ones on their snouts where nostrils might otherwise be expected. They have short horns and short white hair. They are originally from Tractis, which is invaded and largely destroyed by the Earth Empire: a group of surviving Tractites travel back in time to prehistoric Earth using a Time Tree and prevent the human race from ever evolving, colonising the planet, which becomes Paratractis. The Tractites have advanced knowledge of physics. Their "written" language is based on colour and smell. In the alternate timeline in which Earth becomes Paratractis, Noctutis is the capital and Tafalis is another city. The Tractites have lived on Paratractis for so many generations that they are unsure how they first came to the planet. The Vargukonon is a Tractite work. The Uncreator is a being from Tractite mythology who brings about the end of the universe, a legend foretold by the Book of Keeping. Watchers of the Keeping, also known as Keepers, are entrusted to be on the lookout for the Uncreator, who legend states will be a pale biped. There is a Keeper in every Tractite city in the galaxy.
Sam hasn't encountered the Daleks (see Vampire Science), but the Doctor has told her about them on several occasions. The Doctor has also mentioned Jo to her. To her horror, Sam shoots a Tractite dead. Sam contracts an unspecified disease on prehistoric Earth, but is cured by medicine from the TARDIS. She has developed the "Jones-Richter Scale". 1 means the Doctor has misdirected the TARDIS. 5 means that he has landed them in the middle of a war zone. 10 means that he has accidentally destroyed the universe. She says that she's only seventeen. Her parents abandoned her to go on political protests.
The Doctor is familiar with Tractites and has visited the Bror coast on Tractis. He claims that he got his current outfit from Saville Row, but he's still wearing his fancy dress garb from San Francisco and the shoes that Grace gave to him (The TV Movie). He is still trying to fill in gaps in his Strand back issues collection (The Bodysnatcher). He has a Galactic Compendium, YG 7008-7088 in the TARDIS. He has a white cloth sunhat in his pocket. He produces some blue tablets containing an antiviral. Whilst held prisoner by Mauvril, he's starved almost to death, kept alive by a glucose drip. He uses jelly babies containing a vaccine to Hynes' virus to save mankind's ancestors. He knows who Rowenna is, and about Jo's son Matthew. He claims that he hasn't seen Jo for about 300 years.
The TARDIS spends one million years on Earth after the Tractites drop it into a volcanic vent. The Cloister Bell rings here. The TARDIS console room contains a hundred clocks, a model train set [not the one from Model Train Set (Short Trips)], gramophones, a chair with a crown, a phonograph, a ticker-tape machine, and a red crescent first aid kit (hidden behind the harpsichord) - which just happens to have the stuff needed to wipe out Hayes' virus.
If a being from an unstable timeline, or one that is subsequently destroyed, travels out of it in a TARDIS, then they continue to exist even when their timeline is destroyed.
The time trees that the Tractites discovered are six feet tall, have blue and green branches, huge bright orange leaves, and appear to be encased in cold fire. They have an appetite for heavy metals. Picking off a fruit allows travel back in time, though you cannot control it very well. They travel in time by chronon-wave asynchronous transmission. They feed on energy from the universe, meaning that they can only force a divergence in time, not rewrite it. As a result, when a time tree is used to try to force a new universe into creation, it borrows energy from the original universe, destabilising the universe.
Jo Grant has separated from Cliff (The Green Death) and has a son called Matthew. She lives with Matthew in a two-bedroom house in Hackney and has two jobs. She has stayed in touch with Benton. She claims to have been on the UNIT books since 1971. Rowenna Michaels is an old friend of Jo's, who is killed by wild dogs in prehistoric Africa. Jo kills Mauvril's Tractites on prehistoric Earth to save her future.
Regimental Sergeant Major John Benton is still a member of UNIT, although now largely works from a desk. Jacob Hynes is a UNIT Captain.
Links: Sam notes that the label on the Doctor's clothes (which he claims to have picked up on Saville Row 1892) says Party Funtime, San Francisco, and he also mentions the boots he was given by Grace (both from The TV Movie). The Doctor recalls buying a pair of wings in the 2108 January sales (Speed of Flight). Sam mentions Zygons (The Bodysnatcher), Vampires (Vampire Science) and the Doctor's stories about Daleks. Jo recalls her life with Cliff (The Green Death). Jo has told Rowenna about Autons (Terror of the Autons), Axons (The Claws of Axos), and Daleks (Day of the Daleks). She recalls Spiridon (Planet of the Daleks), Xarax (Dancing the Code), and Sea Devils (The Sea Devils). She also recalls the effects of alien viruses from a number of incidents. Benton refers to Bambera (Battlefield). Mauvril met an Earth Reptile from the Empire.
There are also references to Ice Warriors and Zygons. The Doctor mentions Draconians (Frontier in Space, The Dark Path) and Chelonians (The Highest Science, Zamper, The Well-Mannered War). The Doctor mentions Davros to Sam and tells her that he hopes she'll never meet him...
Location: Wray Park, California [c1997]; Kilgai, Tanzania; Hackney, and UNIT UK HQ June 1997; London, 1st January 2108, in an alternate timeline where the Tractites rule the Earth, which is known as a Paratractis; Hackney, London [c1997]; the Rift Valley, Africa, 2,579,868BC and c3,579,868BC.
Future History: In the 23rd Century, they publish sperm-whale songlines. The Earth Empire invades Tractis for its Xantium and Cardinium, enslaving the Tractites and wiping them out when a group become resistance fighters. The Empress' throne contains Draconian galaxite and houses a gold-and-obsidian maganflux drive that is the single most powerful machine in human history, allowing instantaneous travel across the galaxy. Species who pay tribute to her include the Draconians, Zygons, Ice Warriors, and GórEntelech. She declares Tractis (known to the Empire as the Protectorate of Eta Centauri 6) a Royal Duchy, and appoints Earth Reptile Ambassador-General Menarc her ambassador on the planet, apparently at the urging of the Doctor in an attempt to help the surviving Tractites. Menarc announces free elections and the formation of a planet-wide council, although the Earth emigrants eventually form a separatist party and assassinate council members, leading to a bloody war as the Empire starts to collapse.
Unrecorded Adventures: The TARDIS contains the throne of a pretender to the title of the Earth Empress in the early fourth Millennium. The Doctor has visited Tractis. He says that he always wanted to visit the Rift Valley, Africa, at about this stage. The Doctor knows the Venerable Bede (The Talons of Weng-Chiang) and Oscar Wilde. He once bought some wings in the London January sales in 2108.
The Bottom Line: 'We all have to be Daleks sometimes.' One of the better early Eighth Doctor books, with strong, adult, themes throughout. Sam's and Kitig's indecision about destroying the other's race, and the horrific crimes on both sides give this book a sense of gritty realism, and horrific imagery. The plot is good, the characters are good, and you're left wondering who was actually in the right.
'I wanted to go home, Doctor. I wanted to be certain that home was still going to be there.' An interesting, if bleak, morality play, in which almost everybody is forced to commit some kind of atrocity. Thrusting Jo, one of the Doctor's most optimistic companions, to slaughter Mauvril's Tractites, is highly effective.