Darwin and his guests had run some way into the woods by now, and finally the shadows looked normal. Even so, the Doctor studied the afternoon light for some time before she finally puffed her cheeks out and relaxed.
“There should have been another way,” she said to Chris at last, who was still shaking from her experience with the shadow. “I didn’t think it would pounce like that, not on someone as young as you. I thought you would be safe, but I didn’t see how hungry that thing back there was.”
Chris said nothing, looking at the ground.
“You could have taken the knife,” she said. “Tried to cut everything up. You’ve more muscles than me.” She shivered. “ I saw… things,” she said. “I don't want to see them again.”
“A child soldier, Doctor?” wheezed Darwin as he gasped for air. “Dear me, you really don't practice what you preach–”
“–that's not what you are, Chris,” interrupted the Doctor. “Don't listen to the stupid genius over there. I never thought for a minute that thing would attack–”
“Tell me,” said Darwin, is our young friend from after they bring back child labour, or–”
“What?” said Chris.
“Ix-nay on the ild chabour-ay,” said the Doctor. “And it's not like that. The Lethe, they…” she trailed off, a hollowness in eyes.
“...they take the shadow you cast,” she said at last. “Every bad thing you’ve ever done; all the pain you've caused. And me and Charles… we’ve hurt more people than most.”
“I can see how you did,” spat Chris through tears.
”You’re a child. And… well, innocence isn't the word, not exactly. Because I don't want to take away from how awful those things you saw would’ve been. But when the shadow of the Lethe hits another living thing… well, then, it's everything you felt but worse. Unimaginably so. And a child doesn't tend to cast a long shadow.”
“You thought it might hit you,” said Chris.
“Either of us! Me or Charles. If that happened in a space as enclosed as that, we might all have been caught in the shadow’s wake. It’d have torn our minds apart.”
“We’re a feast to them, Chris,” she said, “But I should have seen there was still a risk to you–”
“But you didn’t,” said Chris, putting her hands in her pockets. She walked on ahead, just far enough to feel on her own, making sure to snap as many twigs as possible under her feet.
“I always thought I was good with children,” said the Doctor when she was sure Chris was too far away to hear. “I suppose you need to believe that, if you’re going to be really bad with them.”
Darwin didn’t respond to that, but just stared softly at the ground.
“Ah. Of course. Bad with adults too. I forgot what time of year this was.”
”I didn’t know,” said Darwin sadly, “if you knew there was anything to forget.”
”Of course I did! You’re not the only brains of the outfit. It’s 1881, it’s April, you’re sad and it’s affecting what you do. It’s not like you to get angry at something so petty as a threat of assassination.”
”It’s thirty years since she died,” added the Doctor unnecessarily.
”Next Saturday,” said Darwin. “Silly, isn’t it? To discover so much, yet be troubled by something so small.”
“No life is small, Charles,” said the Doctor. “Especially not the life of your own child. It's a long time since I met Anne, but she was special– not just to her father, but through whatever eyes I had on at the time.”
She looked down the path stretched through the woods, where her child companion walked slouched and defeated.
“Chris reminds you of her,” she said, knowing she should have realised.
“Oh, not really; no more than anyone her age. And you can't go sealing yourself off from children, not for three whole decades. I can see them now without too much of the pain. It's just…”
“...sometimes a child does cast a long shadow,” he said at last. “And perhaps you’ve forgotten that, with her.”
He turned to look the Doctor in the eyes.
“You can't lose her, Doctor.”
“And I won’t! I'm just taking her back to her house, anyway. I'm her cab driver, not her mother. If I thought I was anything else, I might remember… how many people I‘ve lost, I suppose. When travelling with them became like an adventure.”
They both looked back to Chris, who was now quite far away.
“I can be responsible, if I have to be” said the Doctor. “I defend a whole planet, after all. How much harder can it be to defend a child?”
Darwin smiled. “That's exactly the sort of thing everyone says, when they end up with this sort of responsibility. Take it from a scientific genius.” he cackled, “it turns out to be much harder.”
Chris heard the last bit of that, as she hurried on as far ahead as she dared. She had been concentrating intensely on being the exactly right amount of far away, not close enough to feel she was with Darwin and the Doctor, but not so far that they couldn't save her from shadows or baboons.
The leaves grew thick over that part of the forest, and very little light broke through. Still, the shapes of trees still flickered against the grass, their shadows stretching in a way that almost looked like hands.
If the Doctor had been closer to Chris, she’d have said you had to watch out for almost. If a thing was almost like something else, she'd say, you could miss the point when it was better to think that it was that something else after all. She'd have said that if a great big hand of shadow had wanted to hide somewhere, then it might well choose a place where you might mistake it for the outline of a tree. She'd have said safety was an illusion, and that you should always be on your guard. But the Doctor had not kept Chris safe, and now she was too far away.
A two-dimensional blackness twisted through three dimensions, and Chris screamed as she was sucked into a fourth.
The Doctor ran towards the shadows, but it was already much too late.