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
 * Begonia
 * Deadly Nightshade
 * Aisha
 * TARDIS Ryan

The Fleet planet

 * Space Lord Draal
 * Bernard
 * Hydran prisoner
 * Dalse prisoner
 * Chentan prisoner
 * Zraryx prisoner

Tellus IV

 * Willow
 * Parsley
 * Lily of the Valley
 * Oak

Calufrax Major

 * Curatrix
 * The Attendant

New Phaeton

 * Aaron
 * Lalitha
 * Porter
 * Peyton
 * The Faculty
 * M8-Tron

London

 * Tom Manners
 * Mr Delgado
 * Jonathan
 * Jonathan's sister
 * Professor Tarkovsky

Individuals

 * Harry Houdini was known for impossible escapes.
 * 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

 * The Fleet conquered 10,000 star systems.
 * Time Lords have two hearts.
 * 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.
 * Carnivorous chessmen live on Proxima Ceti.
 * The Fleet defeated Murgon III.
 * 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.

Earth locations

 * Ryan saw the Doctor escape 200 cyborg clones of Houdini in the subways of New York City in 1904.

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.
 * The Citadel is 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.
 * Ryan's clothes is made from cellulose-based materials. His shoes are made from rubber and plastic.
 * The Citadel was made of iridanium steel.

Technology

 * Yaz witnessed the Doctor defusing a temporal anomaly bomb on a derelict space station.

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)