It also contains the first casual reference to the Faction Paradox, which become an important element in the BBC books Eighth Doctor Adventures and subsequent spin-off series, and an explicit explanation that the mark carried by the Third Doctor during his exile on Earth was a branding used to distinguish criminals by the Time Lords (in reality, this mark was a tattoo of a cobra that Jon Pertwee picked up while serving in the Royal Navy).
The novel is partly an exploration of Miles's "bottle universe" concept that places Virgin Publishing's Virgin New Adventures series within a bottle universe inside the BBC Books Eighth Doctor Adventures universe (and by extension these bottles are within a larger one containing all televised serials).
Grace's life after her encounter with the Doctor has not been explored on-screen beyond the television movie, although the Doctor did have to deal with the after effects of those events in the spin-off Eighth Doctor Adventures novel Unnatural History, by Kate Orman and Jonathan Blum.
Susan reappears in the Eighth Doctor Adventures novel Legacy of the Daleks by John Peel, which takes place after the events of The Dalek Invasion of Earth.
It also features a character called Hedin, as in Arc of Infinity and the character of Savar is mentioned in the BBC Eighth Doctor Adventures novel Seeing I.
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It features the Eighth Doctor, Fitz Kreiner, Compassion and Romana III- as well as a brief appearance of the Third Doctor in a ghost-like state due to the Faction's manipulation of the Doctor's timeline-, and features the last appearance of Faction Paradox in the Eighth Doctor Adventures.