The Secret in Vault 13 (novel)

 a novel released in 2018 by BBC Children's Books. It was written by David Solomons and featured the Thirteenth Doctor, Graham, Yaz and Ryan.

Publisher's summary
A sinister school where graduation means death...

A monstrous mystery lurking below a quiet London street...

A desperate plea for help delivered by... hang on. A potted plant?

The Doctor has been summoned. The galaxy is in terrible danger, and only a Time Lord can save it. But to do so, she must break in to an ancient vault on a remote and frozen world - from which nobody has ever returned alive...

Can the Doctor and her friends Yaz, Ryan and Graham uncover the shocking secret in Vault 13?

Chapter titles

 * 1) Diddly-dum Diddly-dum Woo-woo
 * 2) Bigger on the Inside
 * 3) Re-potted
 * 4) Gardeners' World
 * 5) Non Compost Mentis
 * 6) The Curatrix
 * 7) Gardeners of the Galaxy
 * 8) Cuppa Tea?
 * 9) The Last Guardians
 * 10) Dorm
 * 11) Please, Miss, I Feel Sick
 * 12) The Faculty
 * 13) Always Keep the Warranty
 * 14) School's Out
 * 15) Exterminate
 * 16) Fantastic Voyage
 * 17) Party Animal
 * 18) Unearthly Child's Play
 * 19) By-laws
 * 20) A Hiccup in Time
 * 21) Kensington Gore
 * 22) Run!
 * 23) We Belong Together
 * 24) The Crack of Doom
 * 25) Breaking Bud
 * 26) An Apple a Day
 * 27) Plants Within Plants
 * 28) Sunset
 * 29) What Would Werelock Do?
 * 30) Always Remember to Back Up

Plot
to be added

Characters

 * Thirteenth Doctor
 * Graham O'Brien
 * Yasmin Khan
 * Ryan Sinclair
 * Willow
 * Deadly Nightshade
 * Parsley
 * Lily of the Valley
 * Oak
 * Curatrix
 * The Attendant
 * Begonia
 * Aaron
 * Lalitha
 * Porter
 * Peyton
 * The Faculty
 * M8-Tron
 * Tom Manners
 * Mr Delgado
 * Jonathan
 * Jonathan's sister
 * Professor Tarkovsky
 * Aisha
 * TARDIS Ryan
 * Space Lord Draal
 * Bernard
 * Hydran prisoner
 * Dalse prisoner
 * Chentan prisoner
 * Zraryx prisoner

Individuals

 * Ryan thinks of Harry Houdini.
 * Space Lord Draal had the hull of a captured Frost Pirate warship and fins of megalovore sharks, which used to inhabit the Outland Sea, in his throne room.

Species

 * Time Lords have two hearts.
 * The Fleet conquered 10,000 star systems.
 * The Doctor previously defeated Sontarans, Cybermen and Daleks.
 * The Thirteenth Doctor encountered carnivorous chessmen on Proxima Ceti earlier.
 * The Space Lord held a Chentan, a Dalse, a Hydran and two Zraryx prisoners in his throne room.
 * Hydrans originate from Polaris Alpha.
 * Giant spiders from Metebelis III have twelve eyes.

Animals

 * Bugbeasts of Zeta Draconis are easy to defeat.

Robots

 * Mark VI combat mechanicals were military robots created by the Fleet.

Planets

 * The Fleet operates from an unnamed planet.
 * Bugbeasts live on Zeta Draconis.
 * Time Lords from Gallifrey are known to the Fleet.
 * Daleks are from Skaro.
 * The Fleet defeated Murgon III.
 * Carnivorous chessmen live on Proxima Ceti.
 * The TARDIS team decides to go to Lotos B but never gets there.
 * The Doctor recalls an orchid seemingly trying to speak to her on Solaria.
 * The TARDIS crew goes Tellus IV to meet with the Gardeners.

Other locations

 * Bernard pursues the Doctor, Graham, Ryan and Yaz through the Forest of Desolation, across the Burning Grounds and into the Valley of Agonies. It was sent from the Citadel in the Blasted Plains.
 * The Fleet was planning to attack the Avolantis System.

Events

 * The Outland Sea boiled away during the Ice Cap Wars.

TARDIS

 * TARDIS is powered by the Eye of Harmony.
 * TARDIS has two "hearts": the engine room and the circular console room with the console.

Materials

 * Mark VIs were made of phlebotinum.

Continuity

 * The Thirteenth Doctor explains that the TARDIS is supposed to blend in with the environment using the chameleon circuit, but it got stuck in a form of a police box circa 1963. (TV: An Unearthly Child, Boom Town)
 * Graham O'Brien was most keen to leave Earth and travel with the Doctor. (TV: Arachnids in the UK)
 * Graham, Ryan and Yaz chose to leave Earth with the Doctor a few weeks ago. (TV: Arachnids in the UK)
 * Graham would not want to run into Ravenous monsters. Incidentally, Ravenous are especially feared by Time Lords. (AUDIO: Seizure)
 * The Doctor recalls how she and Sarah Jane Smith had problems with Krynoids. (TV: The Seeds of Doom)
 * Graham finds a tourist prospect for the Leisure Hive on Argolis, but the Doctor has already been there and had issues with the tachyon generator. (TV: The Leisure Hive)
 * Yasmin Khan never met Graham until their encounter with Tzim-Sha. (TV: The Woman Who Fell to Earth)
 * The Doctor recalls her encounters with Yeti robots. (TV: The Abominable Snowmen, The Web of Fear)
 * They return to water Graham's houseplants a few weeks after first leaving the planet. (TV: The Woman Who Fell to Earth)