Cold Fusion is an original novel written by Lance Parkin and based on the long-running British science fiction television series Doctor Who. It features the Fifth Doctor, with Adric, Nyssa, and Tegan, immediately after Castrovalva. Also appearing is the Seventh Doctor, with Chris and Roz, from between the Virgin New Adventures novels Return of the Living Dad and The Death of Art. It was the only one of the Virgin Doctor Who novels to feature more than one Doctor. Notes The story deliberately contrasts the characterisation of the Fifth Doctor and of the Seventh Doctor in the Virgin New Adventures. In an interview for the BBC, in discussing Cold Fusion, Parkin described the character of Adric as "hopeless with Davison". Parkin has said he was writing a book about the Yugoslav Wars, that is a conflict "where horrible things are happening, and clearly there's a case for international intervention, but … well, there's no clear good guys and bad guys. And that was the idea of the book: two Doctors show up and they look at a situation like Yugoslavia/Syria and they, completely independently, perfectly sensibly, pick a side to support. And they pick different sides, so spend the book fighting each other." He also said he "was never happy with Cold Fusion. It was the second novel I wrote, and I always had the sense it had got away from me, but I'd never been able to explain why. My first, Just War, was very taut, serious, fine-tuned. Cold Fusion was always a lot more ramshackle." Cold Fusion includes many references to the Cartmel Masterplan which would be more fully explored in Lungbarrow. More is learned about the character of Patience in the BBC Past Doctor Adventures novel The Infinity Doctors, also by Lance Parkin. It is suggested that she is the Doctor's (or possibly The Other's) wife, but how she fits into normal continuity is deliberately not revealed. Notably, this novel features a sequence in which the Doctor recalls his life on Gallifrey and in which this earlier Doctor has recently regenerated in a form heavily inferred to be one of the "Morbius Doctors" seen in the mind bending sequence of the serial The Brain of Morbius, specifically the incarnation which was represented by an image of Douglas Camfield. While it is inferred in this book to be an incarnation of the Doctor, the novel Lungbarrow suggests it