"Yasmin? What's wrong?" The Doctor tapped the door of Yaz's room again and waited. It was a sort of evening in the Tardis, or at least late in the day after their most recent adventure.
The heavy door slid back a small amount. "Come in," Yaz said in a quiet voice. The Doctor could not see her. The room was dark. But, even with its crazy self-designing architecture she knew her way about most of the rooms in her own ship.
She stopped in the doorway trying to make out where the bed and the closet might be. "Can I put a light on?" she asked optimistically.
She heard Yaz mumbling to the Tardis A.I. "Low light please." The room brightened a little with a warm orange glow.
Yaz was lying back on her bed. The Doctor recognized the ornate and heavy item as something she had rescued from revolutionary France. But she could not remember why she had done that. Or why it was in this room right now.
Yaz seemed distracted. "I can go if you want," said the Doctor. "We'll have a chat over a coffee in the morning."
"No. Just wait." Yaz sat up on her elbows, clearly tired. The Doctor could see she was still wearing the clothes from their recent trip to Niagara Falls. A dark, heavy, velvety, many-layered skirt and a formal white blouse with very long sleeves. The hat and jacket were thrown on the floor.
"I can let you get changed first, if you want?" said the Doctor. "We had a very long day." She giggled.
Yaz shook her head. "No, I'm fine like this, for now" she said. "That's not the problem."
The Doctor stepped warily into Yaz's room. "Well, my door is always open," she mumbled. "Or yours in this case."
"Close the door, Doctor," Yaz asked. "Please." Her voice was fluctuating.
The Doctor let the door slide closed behind her, awkwardly bumping into it. "I should have brought a brew. Midnight chats are always easier over tea. Or coffee. You like coffee?"
"Coffee," said Yaz shaking her head. "But either's fine. Although I don't need a brew right now." She looked properly at the Doctor. "What have you got on, by the way?"
The Doctor was taken aback. She was still wearing her thrift-shop shirt, the one with the rainbow across it. "What do you mean? I always wear this. Even when I'm off-duty." It occurred to her as she was saying it that the shirt was getting a bit sweaty. "It's my favorite."
"I didn't mean that," Yaz whispered. She lay back trying to settle her head on several large pillows.
The Doctor looked down at her lower half. "Why? What's wrong with this?" She looked at the baggy pyjama pants with a large pink check then further down at the comically large slippers that smothered her ankles. "I don't sleep a lot. But it does help me relax when you all are pretending it's night time."
"It's too fluffy," Yaz coughed. "But, I didn't need help with sleep."
"No," said the Doctor shrugging. "I can usually hear you snoring no matter where my room is."
"Oi. Offensive," said Yaz. "But look!" She sighed then plucked at the blouse around her waist and opened the tiny button above the belt of her skirt to expose a small area of skin below her navel.
The Doctor frowned then strode over to the bed. "Whoa!" Her eyes opened wide. "What has happened there?" Yaz's skin was no longer its normal color. It had become jet black and shiny and metallic.
Yaz showed how worried she was now. "I think it's to do with that scorpion thing we met. When we were in the spaceship. Above New York."
"Aw, the Skithra queen? Yes." The Doctor was almost excited. "This could be some kind of offworld infection." She ducked down to look at the exposed skin. "That is brilliant." The flesh was still soft and flexible, but the shiny shell-like surface looked tough and resilient.
"Uh? I don't think so." Yaz looked from the Doctor to her exposed belly and back to the Doctor. "It's far from brilliant. What happens if it gets worse?"
The Doctor stood up and looked at her quizzically. "I don't know. What if it does?" She ducked down again. "How much of you is covered? Come on. I'll need to see more than this."
"Um, not a lot." Yaz was already uncomfortable with what was happening to her physically. "But it's all the same. All over."
"Oh! So there is more?" She looked at the shirt as if seeing thru the material, then shook her head. "I'll need to get my sonic. See if I can detect anything."
Yaz grabbed her forearm. "No," she said. "Stay here. You'll wake up everyone else. And what good will a detector do? I'm not a piece of technology you can hack into."
The Doctor wriggled her arm free from Yaz's desperate grip then patted her on the hand. "You might be right. But maybe something organic is hacking into you."
Yaz nodded. "So let's deal with that, Doctor." She fixed her gaze on the Doctor, more confident now.
"Well, let me think," said the Doctor. Then she shook her head. "No. All this guessing is no good." She stared back at Yaz. "I'll need to see it for myself."