This novel is set rather uniquely between Genesis of the Daleks and Revenge of the Cybermen; it takes place during their Time Ring travels just after Genesis of the Daleks. Since the Doctor remains separated from his TARDIS from the beginning of former serial to the end of the latter serial, this story sees him borrowing another one temporarily.
It was not the only story to take place between the two serials. The Short Trips entry The Last Thing You Ever See also saw the Doctor, Sarah and Harry travelling by time ring while trying to return to Nerva Beacon. Logically, that story chronologically follows this one.
Sarah is marooned on a slave world where the only escape is death. Harry is caught in the middle of an interplanetary invasion, and has to combine medicine with a desperate mission. And the Fourth Doctor lands on a world so secret it does not even have a name.
to be added
- Fourth Doctor
- Sarah Jane Smith
- Harry Sullivan
- Elyze Brant
- Martyn Daw
- Baal Garikth-tal
- Barris Kambril
- Oliver Malf
- Angelyn Marcavos
- Neels Prander
- Cara Tarron
- Mattew Tarron
- Brin Vender
- Mogul of Tralsammavar
- The Time Lords give the Doctor another TARDIS, one with a functioning chameleon circuit, but he gives it back.
- The Doctor mentions adventures with the Daleks, the Aztecs, Atlanteans, the London Underground, the Peladon and the Minoan labyrinth of Crete.
- The Time Lords reactivate the Doctor's Time Ring, so the Doctor, Harry and Sarah Jane can resume their journey back to Nerva Beacon.
- After departing from Skaro, the Doctor, Sarah and Harry are scattered across the Adelphine Cluster due to temporal disruption interfering with the Time Ring.
- The prologue of the novel contains explicit confirmation that the Doctor's mission in Genesis of the Daleks created a new timeline. The Time Lords actively monitor the changes as thousands of worlds are retroactively liberated from the Dalek Empire, although millions more remain under Dalek rule. The concept of a second timeline in Dalek history branching off from Genesis was introduced in The Discontinuity Guide, as reprinted on the BBC website. Similar revelations were later intended for inclusion in the audio story Return of the Cybermen in 2021, linking the fallout of Genesis to the coming of the Last Great Time War, as well as explaining many other continuity discrepancies, but the scene was ultimately not recorded.
- According to the Time Lords, due to the Doctor's actions, a force of robots will arise that will contribute to the fall of the Daleks. It is implied that these robots are the Movellans.
- The Time Lords observe the fallout from the Doctor's mission to Skaro after he and his companions depart via the Time Ring. (TV: Genesis of the Daleks)
- Sarah recalls Professor J.P. Kettlewell's K1 robot when she interacts with Max. (TV: Robot)
- When recovering her memories, Sarah mentions UNIT and Brigadier Lethbridge-Stewart. (TV: The Time Warrior)
- The Doctor recalls running up and down corridors from Daleks, (TV: The Daleks et al) the Aztecs (TV: The Aztecs) and Atlanteans (PROSE: The Lost Ones, TV: The Underwater Menace, The Time Monster), as well as around the London Underground, (TV: The Web of Fear, Invasion of the Dinosaurs) and Peladon (TV: The Curse of Peladon, The Monster of Peladon)
- Harry compares the ship's medicines to those on the space station Nerva. (TV: The Ark in Space)
- The Doctor tells Harry that if he came into physical contact with another version of himself, the result would be "Bang!" (TV: Mawdryn Undead)
- The Discontinuity Guide to: A Device of Death at The Whoniverse
- The Cloister Library: A Device of Death