“Lady Tchainsaw?”

“That’s the one.”

“But what would the Diberi want with a book about the Flow?” said Effie. “I can’t imagine they’d approve of it. And Jupiter Peacock even wrote it out of his translation of ‘Galloglass.’ ”

The librarian put his fingers in his ears. “La, la, la!” he said. “No more spoilers, please. I can’t know all this.”

“I think this is all connected,” said Effie, but the librarian, who still had his fingers in his ears, completely ignored her.

Lexy took the yeti by the hand and motioned for him to follow her. Poor thing. He looked terrified. But he also seemed grateful to see the sunshine. He let out a deep wail as soon as he saw the sky. Perhaps he was glad to be free. Or maybe he was trying to get a message to his parents, however many miles away they were. Or possibly he was just cold. Mind you, didn’t yetis come from snowy places? Weren’t they sometimes called abominable snowmen? Who knew if that’s what this creature even was. But it was what Jupiter Peacock had called him.

“Shhh,” said Lexy. “We need to find somewhere safe for you. The hospital’s not far. Do you think you can make it?”

But the poor yeti was limping badly. Lexy had done her best with what she had, but the yeti needed more specialist help.

Above them both, the sky was rapidly turning from a clear winter blue into a kind of deep, stormy purple. The wind started to whistle.

“Oh dear,” said Lexy, “I think there’s a storm coming.”

The yeti seemed as if he really couldn’t go any farther. Lexy looked around for a place to hide him. He was far too heavy for her to carry. There was an old Portacabin just by the back entrance to the university that would have to do. It was green and sort of moldy on the outside, but warm and dry inside.

“You’ll have to hide under a table if anyone comes,” said Lexy. She couldn’t be sure whether he’d understood her or not. If only Raven were here. But maybe even Raven didn’t speak whatever language yetis understood.

Lexy drew her school cape around her and hurried toward the Old Town Hospital—not the official one, but the secret one, where Odile Underwood worked. By the time she’d got to reception the sky had grown a darker shade of purple and large wet flakes of snow had started drifting nonchalantly out of the sky as if they didn’t care about yetis, secret books or the end of the world.

Lexy looked quite bedraggled as she approached the receptionist and asked to see Odile.

“Nurse Underwood isn’t here,” came her reply. “She’s doing home visits today.”

“But it’s urgent,” said Lexy. “Can someone page her, please?”

“Well . . .”

“Please,” said Lexy. “It’s really important.”