The Runaway TARDIS (novel)

 was a novel released in 2020 by Quirk Books, as part of their Pop Classics range. It featured the Thirteenth Doctor with a new companion, Lizzie, a child who's run away from home. It was illustrated by Kim Smith, and the story was devised by editor Rebecca Gyllenhaal.

Publisher's summary
Lizzie is running away. She hates her new house and her new school, so she packs a bag full of peanut butter sandwiches and says goodbye to her family. But when she stumbles upon a mysterious blue box in the woods (that's bigger on the inside!) Lizzie embarks on a much grander journey than she had planned. The box is called the TARDIS and it's piloted by a mysterious woman called the Doctor, who claims to be a time-traveling space alien! Lizzie doesn't like new places, so she asks to be taken home. But when she accidentally drops a peanut butter sandwich down the console, the TARDIS malfunctions, and the Doctor is no longer able to steer! The Doctor and Lizzie embark on a wild adventure through time and space, visiting the Pyramids, dinosaurs, the surface of an alien planet, and more. But will Lizzie be able to get back home? And will she learn that new places aren't so bad after all?

Plot
On her first day at a new school, Lizzie eats lunch alone. Upset that she was unable to make any friends during the school day, as soon as she gets home, she decides to run away to her old neighbourhood; she makes a dozen peanut butter sandwiches and puts them in her backpack. Despite being unsure of the way, she heads into the woods behind her house, starting to eat one of the sandwiches she had packed.

Seeing a mysterious big blue box, out of curiosity, she opens the door to look inside; she is surprised to find that the box is bigger on the inside. She investigates the console and accidentally drops her peanut butter sandwich down a slot. As she hears the door opening, she hides under the console and sees a woman wearing a long coat, who begins to operate the controls; the TARDIS takes off, but then a klaxon sounds and lights begin to flash. Lizzie is shunted from under the console.

The woman itroduces herself as the Doctor, and she opens the TARDIS door. Lizzie is startled to find that they are in outer space. The Doctor, concerned that the TARDIS is malfunctioning, says that they landed in the Brouhaha-Nine-Nine-Five Galaxy, rather than the Silfrax Galaxy, where the Doctor intended to go. After the Doctor tells Lizzie that the TARDIS is a time and spaceship and that although she may look like a human, she is an alien, the Doctor asks her if Lizzie got peanut butter in the console. Lizzie confesses that she did, and the Doctor tells her that since she has misplaced her tool box and her sonic screwdriver doesn't work on peanut butter, they could only travel in the TARDIS using the randomiser.

The TARDIS lands in clearing that is filled with dinosaurs; Lizzie is terrified as she discovers this. After this, they land in Egypt, where Lizzie recognizes the pyramids and the Great Sphinx. Next, the TARDIS lands underwater--in a coral reef. The Doctor and Lizzie peer out the windows at the tropical fish; Lizzie is surprised at the variety of species of fish.

Then, they land on the Planet Plorp; The Doctor is relieved to discover this as the Glorp, who live there, will be able to help them fix the TARDIS. Lizzie stands by with Blorp, the smallest of the Glorp, while the Doctor and the rest of the aliens work on the ship. Blorp comments on the pleasant smell coming from Lizzie's backpack; in response Lizzie offers them one of her sandwiches, which they thoroughly enjoy.

The Doctor and the Glorp engineers find themselves at an impasse when the Doctor realizes that they will need a neutron flow converter, which she does not have, to reverse the polarity of the time configurator. Lizzie proclaims that she knows how to fix the TARDIS and holds Blorp, the only one small enough to fit into the slot where Lizzie dropped her sandwich, over the console. Blorp goes down the slot, finds the sandwich, and makes quick work of eating it.

The Doctor gives the TARDIS a test run; they are able to take off without triggering any alarms. Now that the Doctor would be able to take Lizzie home, the Doctor and Lizzie hug all of the Glorp goodbye. Blorp tells Lizzie that they wish they could go to Earth with her. Lizzie is sad that she would have to leave the Doctor and the Glorp behind; the Doctor comforts her, saying that she knows how hard it is to have to say goodbye to old friends and to start over. Although she is concerned that the Doctor might be lonely, the Doctor assures her that, even though everyone experiences loneliness occasionally, she always remembers her old friends while also making new ones as she travels.

Lizzie and the Doctor say farewell, and the Doctor drops Lizzie off at the same time that she left, where Graham, Ryan, and Yaz are waiting for the Doctor. Lizzie hurries home.

Lizzie's parents meet her at the front door. She tells them of her adventures with the Doctor, concluding that after that, making new friends would not be that difficult.

Lizzie goes to her bedroom, opens her backpack, and discovers that Blorp has stowed away! They share the last remaining peanut butter sandwich.

Characters

 * Thirteenth Doctor
 * Lizzie
 * Blorp
 * Ryan Sinclair
 * Yasmin Khan
 * Graham O'Brien
 * Lizzie's mother
 * Lizzie's father

Worldbuilding

 * Lizzie drops a peanut butter sandwich into the TARDIS control console, causing the Doctor's TARDIS to malfunction.
 * The Doctor takes Lizzie to the Brouhaha-Nine-Nine-Five Galaxy, the time of the dinosaurs, Egypt, a coral reef at the bottom of the ocean, and finally to Plorp.
 * The Doctor was attempting to go to the Silfrax Galaxy when the TARDIS malfunctioned.
 * When in Egypt, Lizzie recognises the pyramids and the Great Sphinx from her history book.
 * In Egypt, three men are seen riding camels.
 * In Lizzie's bedroom, toys resembling an Adipose and Cyberman can be seen, as well as a sloth wearing a fez.

Continuity

 * Lizzie becomes a companion by stowing away aboard the TARDIS, just like Steven Taylor, (TV: "The Watcher") Zoe Heriot, (TV: The Wheel in Space) Sarah Jane Smith, (TV: The Time Warrior) Leela, (TV: The Face of Evil) Adric, (TV: State of Decay) Trix MacMillan (PROSE: Timeless) and Tara Mishra. (COMIC: Official Secrets)
 * Ryan, Yaz and Graham are seen returning to the TARDIS as Lizzie heads home. The Doctor has been known to drop them off between their travels together, without doing any solo travels during that time. (TV: Spyfall, Fugitive of the Judoon, Can You Hear Me?)
 * The Doctor tries to take the TARDIS to the Silfrax Galaxy, (TV: The Unicorn and the Wasp) but ends up in the Brouhaha-Nine-Nine-Five Galaxy instead. (AUDIO: The Lamentation Cipher, The Viyran Solution)