Kitty (Thin Ice)

Kitty was a 15 year-old girl living on the streets of nineteenth century London.

During the frost fair of 1814, Sutcliffe's men paid Kitty and other homeless children to lure people to the fair on the frozen River Thames to be fed to the creature he had trapped underneath.

Kitty would also con people with her friend Spider to get food or money. During one such con, she met the Twelfth Doctor and Bill Potts. While she distracted them, Spider snatched the Doctor's sonic screwdriver and they fled, only for the time travelers to catch up to them. Kitty and Spider ran out onto the thin ice, only for the creatures to surround Spider. Kitty could only watch in horror as her friend was then sucked under the ice not before the Doctor retrieved his sonic screwdriver.

Distraught by the death of her friend, she made her way back to her shelter but met the Doctor and Bill again who explained they intended to help them. The Doctor gained their trust by giving them food and in exchange they informed him of Sutcliffe's men paying them to lure people onto the ice.

The next day, Kitty went to frost fair again. She met Bill again who told her of Sutcliffe's plan to blow up the ice and feed everyone to the creature. Kitty then proceeded to cause people to panic by telling them the ice was melting, prompting them to get off the Thames before anyone was killed.

The Doctor later modified Sutcliffe's will and made Kitty and the other orphans his heirs, allowing them to live inside his mansion. (TV: Thin Ice)