Addams

Addams was captain of a Vinvocci salvage team that had come to Earth to retrieve the Immortality Gate, a Vinvocci medical device that could rewrite the medical templates of entire planets.

Biography
Addams and her partner Rossiter discovered that the billionaire Joshua Naismith had acquired the Gate in order to provide his daughter with immortality. Addams and Rossiter used Shimmers to disguise themselves as human technicians. Using this cover, they set about repairing the Gate in order to transport it back to their ship. Addams found the Shimmer uncomfortable, and deactivated it whenever she could.

Their progress was too slow for Naismith, who set about finding an expert who could fix the Gate more quickly. He had the newly resurrected Time Lord, the Master, captured and brought to the mansion. While Rossiter worried that another non-human would blow their cover, Addams decided that this expert might prove useful in fulfilling their mission. Addams watched from her makeshift laboratory in the basement as the Master quickly repaired the Gate.

The Tenth Doctor and Wilfred Mott infiltrated Naismith's mansion and discovered Addams there. The Doctor immediately saw through Addams's disguise and deactived the Shimmer with his sonic screwdriver. Addams and Rossiter explained the purpose of the Immortality Gate to the Doctor.

As the Master used the Gate to transfer his personal genetic template across the entire human population, Addams and Rossiter watched, helpless, from their basement laboratory as the readings from the Gate began going haywire. She escaped, along with Rossiter, the Doctor, and Wilf to her ship that was waiting in orbit around the Earth. As captain, Addams decided to evacuate the area, but the Doctor used his sonic screwdriver to disable the ship.

When the Doctor decided to use the ship to return to the Naismith mansion, Addams worked navigation while Wilf and Rossiter warded off the Master's missiles from laser pods. The Doctor leapt from the ship's hatch as it sailed over the mansion, and Addams dropped Wilf off before presumably leaving with Rossiter. (DW: The End of Time)

Personality
Addams was calmer than Rossiter, and was good at making decisions under stress. She sought to avoid trouble wherever possible. This put her into conflict with the Doctor, whom she angrily labelled an idiot. (DW: The End of Time)