“There’s a lunchtime lecture series I thought you might like. Mrs. Marsh told me all about it. Ramsay said he’d mind the shop.”

Carmen eyed him carefully. “Is it about the Antarctic?”

He shook his head. “It’s about the Ormiston Yew.”

“The what?”

“A very famous tree.”

“Oh. Oh no. No.”

“I’m your boss,” said Mr. McCredie.

“Oh my God, you have been speaking to Mrs. Marsh.”

“She’s formidable,” he said.

“You say that like it’s a good thing!”

“Come, come, you’ve been working too hard. You need a break.”

And he swept her out, completely surprised.

SLIGHTLY OVERAWED AND out of breath from marching down the bridges to George Square, Carmen approached the lecture theater behind a briskly walking Mr. McCredie. This was the very heart of the university, full of students streaming past, confidently shouting out to one another, popping in and out of buildings.

She slipped inside the lecture theater, expecting them at any moment to be stopped or challenged, but nobody even glanced at them.

The room was completely full. She scooched up next to a girl who didn’t look best pleased to have Carmen obscuring her view. When she looked up, she realized that everyone else had laptops and iPads open or notepads. A big sign on the board read “THE ORMISTON YEW,” and there was a slide of a tree that looked the size of a small town. Oke was in the middle of talking, gesticulating at the slide.

“So, here it is, the Ormiston Yew . . .”

This layering yew was already old when Mary, Queen of Scots, was born, when it was mentioned in an earl’s documents as providing shelter in 1474.

“Beneath this tree George Wishart and John Knox preached, beginning the Reformation that swept this land, which led to the university itself as a seat of learning.

“There is a reason its exact location is kept quiet—and once again I apologize for not taking you on a field trip”—there was a ripple of laughter—“but if you take the 131 one of these days, stop before the humpbacked bridge, double back, cross the bypass, and find the lane that says ‘private’ on it . . . Follow that for long enough, take the left fork . . . Well . . .” He smiled.

“Is it there?” asked a voice.

“I couldn’t possibly comment,” said Oke, smiling again.

The huge yew tree in the picture looked like a forest above his head. Surely it can’t just be one tree? Carmen thought, looking up.

And then she looked back at him, at the lectern, standing tall, not bouncing for once, but steady in front of his audience, in control, completely engaged. He seemed a completely different proposition from the jaunty boy in the scruffy clothes.