When Carla's new foster baby Lulubelle is kidnapped by human-eating goblins, Ruby boards their flying ship and formally meets the Doctor.

On realising the Bogeyman was created for the children's entertainment, Ruby helps the Doctor save it from being ejected into space.

In "Boom", Ruby attempts to help the Doctor after he steps on a landmine on a war-torn planet, only to be shot down by a soldier, mistaking her for a threat.

After twenty years living alone, Ruby discovers the fairy circle made reference to future Prime Minister Roger ap Gwilliam (Aneurin Barnard), whom the Doctor had mentioned almost brought the world to nuclear war.

Ruby bonds with Emily (Camilla Aiko), one of the guests, as the party is invaded by Chuldurs, intending to "cosplay" as the human race.

This leads to Ruby falling into a trap planted by the Doctor and bounty hunter Rogue (Jonathan Groff), intended to send the Chuldurs to an alternate dimension.

Using a "Time Window" developed by the organisation, Ruby simulates the night her mother left her outside the church but is still unable to identify her.

Ruby later witnesses the return of Sutekh, an ancient enemy of the Doctor's, and takes shelter in the Time Window.

In "Empire of Death", Ruby uses the Time Window to create a "memory TARDIS", allowing her, the Doctor and Mel Bush (Bonnie Langford) to escape Sutekh as he destroys the universe.

[7][8][9] However, in April 2024 it was announced that Gibson and Sethu would appear concurrently throughout the series, with Davies stating that Ruby's character had been conceived around a two-series arc.

"[13] Ed Power from The Independent mentioned that Gibson's performance made her "immediately likeable", calling Ruby "a wonderful new companion".