Nova was a human companion of the Ninth Doctor.
An 11th-Generation Human refugee, she faced starvation and poverty after an economic crash on the Outer Worlds. She was offered indenture at the Sphere of Freedom and her parents accepted as they felt it was her only chance for survival. Prior to her indenture, her family - primarily herself and her father - were keen fans of the vintage show known as “Professor X” and was thus a “keen amateur” when it came to time-travel.
Original Timeline
Ravagers Timeline
At some point, she encountered the Ninth Doctor after he arrived there from following time eddies and accidentally ended up following her. She was initially suspicious of him, but eventually agreed to help him after explaining to him what the Sphere of Freedom was and explaining her situation. In return, he agreed to take her somewhere better afterwards.
After helping him find the Central Ark, he disappeared into his TARDIS for 3 weeks to her chagrin. When he returned, he revealed he had upgraded her security-levels and asked her to help him in his plan to