When they got to the hospital, Chris’s spirits didn't improve. The Doctor and her mum talked about her for ages, as if she wasn't there in the room at all. They used words she didn't understand and words they thought she didn't understand, and she felt like a broken appliance rather than a person. After what seemed like a thousand days the Doctor said she wanted to talk to Chris alone, and with reluctance her mother left the room.
“Sorry about that,” said the Doctor. “It's what grown ups want, to talk about children as if they weren't there. Your mother’s gone now, so we can be honest with each other.”
Chris braced herself. The worst sort of adult tried to get you on side, as if they understood you when in fact they didn't at all. You're not like me, Chris thought, you don’t remember what it’s like to be a child. The Doctor would pretend, though; Chris knew the drill. She knew the sort of thing this woman was going to say.
“So,” said the Doctor. “I'm an alien.”
Chris had been wrong.“Is this a test?” she found herself saying at last.
The Doctor looked confused. “I'm not sure what you mean.”
“You know, a psychiatric test. You say something that can't be true, to see if I'll go along with it?”
“Oh!” said the Doctor, “That’d be clever! No, nothing like that. I'm just saying it ‘cause I'm an alien. From space. Up there!” She pointed at the sky. “And down there.” She pointed at the ground. “And, uh, sort of everywhere.” She waved her arms around. “That's the thing about space, really.”
“You don't look like an alien,” said Chris, feeling silly as the words left her mouth.
“Oh? And what should an alien look like?”
“They–” Chris stopped. Like lots of eyes and tentacles, a part of her was going to say, or — said a darker part — like a man with a skull instead of a head. But she suddenly realised an alien might look like something else entirely. She had once read about a mantis that pretended to be a flower, and was good enough at it that a bee would land on it for it to be gobbled up. What if an alien worked in the same way? If they just looked and sounded like normal people, and seemed perfectly ordinary until it was too late for you?
“I guess an alien could look like you,” she said, hoping she wouldn't be gobbled up. A thought struck her. “Are all the doctors in this place aliens? Are all the doctors in the world?”
“Ha! No. And I haven't been in this place long. I just sort of landed here and had people asking who I was. I said I was the Doctor, and they asked what my specialism was, and I said I was a sort of doctor… of the mind, and one thing led to another, and here I am.”
“I showed them this,” said the Doctor by way of explanation, waving a blank piece of paper in Chris’s face.
“That's a blank piece of paper,” said Chris.
“Yes, but they didn't know that! They thought it was a qualification from the country’s most respected school of medicine, and things worked out for me after that.”
“But that’s not on,” said Chris. “You can't go practicing medicine without a qualification, even if you are an alien. You wouldn't know what you were doing. People might die.”
“You're quite right,” said the Doctor. “That's why after I got here I had to get myself a qualification. From the country's most respected school of medicine.”
“But doing that must take a long time?”
“Oh, many years. But that's okay.” She leant in to whisper at Chris, although no one was listening. “I have a time machine”. She smiled. “And that's not another test.” Chris had no idea whether to go along with this, or protest, or give up talking altogether, so decided she should change the subject entirely.
“I suppose all that might be true,” she said. “But even if you are an alien with a time machine, in the end you are still my psychiatrist. My mother’s wanted me to meet you for weeks now; she's been really worried about me. But you haven't asked anything about me, or my condition. You’ve just talked about yourself for a while.”
The Doctor didn't respond to that, not for a while. She just looked sad, and old, and distant. For the first time, Chris noticed her eyes and the look that was in them, a gaze that melted fire and stopped the sun. She was an alien, then, Chris knew. It hadn't even been a very good disguise.
“Your mum told me about what you saw,” the Doctor finally said. “A man with a skull for a head, following you through every thought. Telling you terrible things. And she told me what happened to your friends, to make you afraid.” She knelt down by Chris to look her in the eye.
“I'm not an adult, Christina,” she said, “however much I look like one. And I wish I was, because someone in your situation should have an adult to talk to, because I know how that really matters. And I'm sorry it’s me, who has to be saying what I’m about to now.”
She stood up and looked out at the window, light casting a snaking shadow.
“They're called the Nack,” she said, “and they're hard for me to explain. Only children can see them, and there’s only a few who can…”
There was a knock at the door. Chris’s mother was calling her name.
“We don't have much time left today,” said the Doctor, “but I have to tell you this. The skull men are real, Christina. They’re real, and it's okay to be terrified of them, because what they do to people is a terrifying thing. I'm trying to stop them — and I will — but until then things might get a bit difficult for you. Don't feel bad, not for being scared. Sometimes it's okay to be afraid.”
“Thank you,” said Chris, turning towards the door.
“Thank you,” said the Doctor. “Goodbye, Christina.”
“It's Chris,” said Chris, “and that isn't a boy’s name.”
“Of course it isn't. I lost a friend recently, and she didn't have a boy’s name either. Goodbye, Chris.”