The Time Vortex whirled past the windows, which were really just modified plasmic shells, reflecting what was outside, inside. Having given up on trying to whittle more information from Koschei, Oliviana had retired to her private suite in the TARDIS in order to dress in a style more appropriate for the Earth year 1482.
The TARDIS was accommodating to the young Time Lady, to be fair; the wardrobe's doors opened wide to reveal that the wardrobe is bigger on the inside than the outside, as was the norm for objects with dimensional transcendentiality. Oliviana wandered through the rows of exquisite garments, organized by planet, then by historical era, until she found the right row of clothes.
She brushed her hand across a silky gown the color of cooled charcoal and she considered pulling it off the rack, stopping mid-action as she spotted a garnet-colored gown lined with ermine; she pulled the garnet gown off the rack instead, gravitating toward the color of her Prydonian chapter on Gallifrey. While no one on Earth would realize the significance of the color, and neither would she or Koschei after they used the Chameleon Arch, she decided it was only right to wear the color for one last time.
The gown felt like the softest velvet. Noticing the deep v-neckline of the gown, Oliviana rummaged through the racks until she found a golden undergown to wear under the top gown. Excitedly, Oliviana pulled off her current clothing and pulled a soft chemise over her head, followed by the undergown, and finally the garnet gown.
Moving to a different section of the wardrobe, Oliviana gazed among the thousands, possibly millions, of glittering jewels. She picked up a thin belt made of the darkest sapphires she had ever seen, and fastened it high around her waist. She gathered more pieces of jewelry that matched, and walked over to a mirror to finish getting ready.
Oliviana gathered her long brunette hair into a simple half-up hairstyle and fastened it with one of the jeweled clips. Next, she fastened the small jewel clips randomly throughout her hair. She put simple jeweled earrings in her hair and fastened a jeweled bracelet around her left wrist.
As she did this, she had to give Koschei a little more credit- he had told her more of the plan; he just didn't tell her what she wanted to know. When she had packed to leave earlier, he had traveled to the place they would go to make arrangements with the family they would be staying with. He told her that he had made a deal with the family- he would give them all the jewels they could ever wish for in return for allowing them to join their family for a temporary period of time.
Realizing Koschei was holding out on her once again, Oliviana hounded him until he relented and revised his last statements. The family they would be staying with was royal; for a reason that Koschei would not disclose to her, the Duchess was missing and the family was in desperate need of a replacement, a female who happened to look exactly like the missing duchess.
And as luck would have it, Oliviana was the spitting image of the missing duchess.
No, she thought, it wasn't luck. It seems that one of the devices Koschei had put together years prior to their escape was a modified species detector.
Normal species detectors worked by seeing an image of a creature, matching the image against a database of known species, and then returning the identification of the species of the creature to the user.
Koschei told her that he called his modified device the Image Identifier and he used it on her without her knowledge before the Feast of Omega, before he had finalized their escape plans. He fed the device her image. The device matched her picture against a database of images of humans throughout all time.
He knew that with the billions and billions of humans that had ever, or will ever, exist on Earth, at least one had to match. And one did- Mary, the Duchess of Burgundy.
It was fitting that she would replace a duchess, seeing as she was the Duchess herself.
Oliviana had protested at first, but Koschei assured her that he found a way to be by her side when she was the Duchess of Burgundy, as her tutor. She was still so unsure of the entire plan, but Koschei assured her that promptly after she used the Chameleon Arch, he would use it right after her.
Koschei explained that he would program the Arch to allow him a short period of time to remember his Time Lord identity, just long enough to get them both out of the TARDIS and to the location where he had specified to the family that they would meet up. By the time the family arrived, Koschei would have already forgotten his Time Lord identity, reverting to the human identity he wrote for himself.
Oliviana played through the plan in her mind over and over again as she descended the staircase from the corridor her suite was located in to the main console room. Koschei stood next to the Chameleon Arch, dressed in fifteenth-century attire as well.
"You look beautiful, Duchess," he complimented, taking her hand and leading her to the device.
Oliviana inhaled deeply as he lowered it to her head and placed the wires on her face and other various parts of her body. "Promise nothing will come between us, Koschei," she said, letting out a shaky breath, fear in her hearts and her mind.
Koschei's eyes softened and he placed one hand to cup her cheek, the other hand gripping the controls. "I promise nothing will happen."
Oliviana nodded bravely. "Then do it."
Koschei set his jaw, turned away from Oliviana, and activated the Chameleon Arch.