Dark Planet (novel)

Dark Planet was a Decide Your Destiny book released in 2007.

Publisher's summary
Join the Doctor and Martha on their travels through time and space and influence the story with your decisions. Choose a direction and let the adventures begin...

Earth is divided. The Upsiders live in luxury while the Downsiders scavenge in the dark world below. Can you help the Doctor and Martha bring the two conflicting sides back together?

Worldbuilding

 * At some future point, Earth is divided into the Up Side and Down Side.

Characters

 * Tenth Doctor
 * Martha Jones
 * Peyton
 * Teah
 * Akemi