The pothole-pitted tarmac wound up over a grassy rise, to open out on a panorama across the machair towards the beach. Spring flowers bowed in the wind, and clouds hovered around the distant mountains that ringed the sands. No matter how often Fin had seen it, this was always a sight that took his breath away.

The school sat out on its own, a tiny collection of grey and yellow buildings and a football field a stone’s throw from the beach. It would be hard to imagine a more idyllic setting for a childhood education.

As Fin drew his car into the little car park in front of the main building, half a dozen kids in crash helmets were receiving road-safety lessons on their bikes, weaving in and out of red traffic cones laid along the road by their teacher.

Gunn called to her as he stepped from the car. “We’re looking for the headmaster.”

“Headmistress,” she called back. “The building to your right.”

The building to their right was yellow-painted roughcast, with a mural of an underwater seascape painted on the gable end. Inside it smelled of chalk dust and sour milk, and took Fin tumbling back through time to his own childhood.

The headmistress left her class trying to solve an arithmetic puzzle and took the two men into the staffroom. She was delighted to be able to tell them that her predecessors had taken great pride in preserving an archive of the school, a tradition that she herself was anxious to perpetuate, and that they had a record of school registers going back to before the Second World War.

An attractive woman in her middle thirties, she fussed over her appearance, constantly sweeping a stray strand of chestnut hair behind her ear where the rest of it was drawn back in a bun. She wore jeans and tennis shoes, and an open cardigan over a T-shirt. A marked contrast with the severe middle-aged ladies who had taught Fin at that age. It didn’t take her long, searching through boxes of old registers, to retrieve those spanning the time when Tormod would have been there.

She flipped back and forth across a period covering the mid forties to early fifties. “Yes,” she said at last, stabbing a finger at the yellowed pages of the old school records. “Here he is. Tormod Macdonald. He was a pupil at Seilebost Primary from 1944 to 1951.” She ran a pink-painted nail down the faded entries that recorded daily attendance. “A good attender, too.”

“Might he have had any brothers or cousins at the school?” Gunn asked, and she laughed.

“He may well have done, Detective Sergeant, but there have been so many Macdonalds here over the years it would be almost impossible to tell.”

“And what school would he have gone to from here?” Fin wondered.