The Time Lords intercept the time ring and send the Doctor, Sarah, and Harry to Deep City, in search of a weapon capable of defeating the Daleks. However, once there, they discover that Deep City has a far deadlier secret - one that could mean the destruction of the entire universe.
Sarah Jane Smith and Harry Sullivan.
None. The TARDIS doesn't appear as our heroes are travelling via Time Ring.
This follows on directly from Genesis of the Daleks.
Pg 1 "Time cracked down the middle." The suggestion here is that the Doctor changed history with Genesis of the Daleks.
"Brastall, Senior Monitor and Cardinal of the Arcalian Chapter, studied the great fifth-dimensional hyperglobe display that hung in the centre of the chamber." The Arcalian Chapter was first mentioned in The Deadly Assassin.
"Four point six on the Rassilon scale, your Grace" Rassilon was first mentioned in The Deadly Assassin.
Pgs 1-2 "Invisible time fields arrayed in hyperspace about the space-time coordinates of the planet Skaro contracted."
Pg 2 "Time dams and tachyon mirrors controlled and redirected the flow as the probability bow wave washed out into the universe" The Time Monster, The Leisure Hive.
"On a thousand worlds the Dalek wars would become a fading memory, then a myth, then nothing." The Daleks were first seen in The Daleks and the Dalek wars have played out in the background of several stories.
"Due to the efforts of their agent and his companions the expansion of the Dalek empire had been delayed, but not halted." Genesis of the Daleks.
"Perhaps a thousand worlds had been saved" This might be a reference to the "thousand years" at the end of Genesis of the Daleks.
"A Prydonian after all, and hardly an outstanding one at that." The Deadly Assassin.
"Have you a fix on the Time Ring?" Genesis of the Daleks.
Pg 3 "It's following the Time Ring's artron trail" Artron energy was first introduced in The Deadly Assassin.
Pg 20 "He crossed to a stand on which a silvery rod a little over a handspan long rested. It had raised bands set along its length and a transverse ring mounting on one end." The sonic screwdriver.
"He moved over to a second stand bearing a broad copper bracelet with a scrolled device mounted on it." The Time Ring (Genesis of the Daleks).
Pg 23 "I remember darkness and spinning round." Genesis of the Daleks.
Pg 36 "He hoped a Dalek wasn't suddenly going to appear" Genesis of the Daleks.
Pg 40 "Well there hadn't been a chance to recover from the hectic time on Skaro yet." Genesis of the Daleks.
Pgs 43-44 "'Medicine by numbers' he remembered saying to Sarah while using the advanced medical kit on the Nerva space station" The Ark in Space.
Pg 48 "She recalled a war, huge domes, and misshapen people. Sinister conical shapes and harsh, grating voices; a dash through tunnels and a final explosion" Genesis of the Daleks.
"Yes, she had acquired these clothes on Skaro, during the war between the Thals and the Kaleds." Genesis of the Daleks.
Pg 49 "UNIT, Brigadier Lethbridge-Stewart, the Doctor, Harry Sullivan, the TARDIS, that was it." Sarah has been working with the Brigadier and UNIT since The Time Warrior.
"It had been transporting them, via soem interdimensional shortcut through time and space, away from Skaro and back to the TARDIS." Genesis of the Daleks.
Pg 91 "I mean the Daleks, Aztecs, Atlanteans, the good old London Underground, Peladon, the Minoan labyrinth of Crete -" The Daleks et al; The Aztecs; The Underwater Menance and The Time Monster; The Web of Fear; The Curse of Peladon and The Monster of Peladon, The Time Monster.
Pg 109 "The deck seemed firm under her feet, so the ship was either under constant drive or it had artificial gravity like Nerva Beacon." The Ark in Space.
Pg 125 "But if it is just a machine, why am I doing this, she wondered, even as she levered the synthoid over a second time. For the same reason people talked to cars?" This is very similar to Sarah's interaction with Kettlewell's robot and what Miss Winters says of her in response (Robot).
Pg 150 "I know: Kettlewell's robot." Robot.
Pg 151 "But whether he is or not I won't let him end up being driven mad like Kettlewell's robot." Robot.
Pg 156 "One of the guards put his sonic screwdriver, copper bracelet and a few more confiscated pocket-sized electronic devices on the table before Kambril and Andez." The copper bracelet is the Time Ring (Genesis of the Daleks).
Pg 191 "We were on out own way back to our own TARDIS travelling by, uh, other means, when we got diverted." Revenge of the Cybermen.
Pg 256 "An hour later, coat, Ring and scarf recovered, they wer ein a tube capsule speeding along towards the port." Genesis of the Daleks.
Pg 258 "After your relative failure to halt the development of the Daleks on Skaro" Genesis of the Daleks.
Pg 259 "Our latest projections now show a force of synthonic robots originating from this facility will, in future times, contribute significantly to the Daleks' final demise." The Movellans, Destiny of the Daleks. (The robot on the front cover even has a hint of dreadlocks.)
"There's another trifling matter we wish you to attend to first." Revenge of the Cybermen.
OLD FRIENDS AND OLD ENEMIES
Pg 1 The Time Lords appear.
Pg 2 Brastall is very likely the same Time Lord seen at the beginning of Genesis of the Daleks.
Pg 259 It's strongly implied that the synthonic robots will go on to become the Movellans.
NEW FRIENDS AND NEW ENEMIES
Cara Tarron, Brin, Chell'lak, Max, Malf, Kambril, Andez, Emberley, Tramour'des.
Pgs 38-39, 44 The Jand, aliens that resemble deer or goats walking upright with golden hair on their faces and small horns.
Pg 46 Reptillians with greenish-blue iridescent skin and eyes protruding from the top of their bone-plated heads.
Pg 10 Deepcity, an underground city on an asteroid. It's the far future, as these are explicitly humans.