The gunsight moved gently across, onto the stranger himself. How had they not let themselves see it, that the new teacher’s mastery of science was a cover for darker arts? In his crate of equipment from the mainland, Benjamin Hailey had brought pestle and mortar, glass globes, a cauldron, ingredients for potions. The man had stolen a canister of gas and showed no aversion to making fire. These were the ‘objects’ spoken of in Jacob Crane’s letter, objects to be feared and refused.

Talk turned quickly to the stranger’s likely dismissal. Though he could be released from his teaching post, there would be no means of ejecting him from the island until the boats restarted in April. Did that prison room still exist up at the Big House? some enquired. It was time, they agreed, the situation grave enough, that someone alerted the Earl. Yet Mr Crane, keeper of the children’s morals, keeper of the principles of the whole population, seemed intent on rehabilitation, not punishment. His letter in their hymn books had been nothing but a shrewd method of recruiting an island of watchful eyes, a righteous army to show their wayward newcomer the right path.

Mr Crane had not admitted this in so many words, of course; he had kept his counsel on who was the true target of his explosive epistle. He would only say that ‘a soul knows its own stain’, and that those who have transgressed should ‘bring forth their offering of turtledoves’. But it could be made to add up. The lovely Miss Cedars and the impressionable Eldest Girls were not perpetrators; they were victims. This was not the island’s occult history repeating itself; this was a virus from the mainland.

Britta, Anna and Jade-Marie had recently been taken under the new teacher’s wing. The girls had been convinced – by Miss French, it was said – to choose a science as one of their A-Level options, to make the most of Mr Hailey’s arrival at the school. On Fridays from October, Dellie Leven taught the younger seniors while Mr Hailey gave the girls some ‘practical scientific experience’ – the phrasing of the gossipers (suggestive emphasis placed on the word practical).

Wary of the mathematical demands of chemistry and physics, the girls had opted for biology, the study of nature, life and human beings. In that classroom, that laboratory, under the tutelage of Mr Hailey, the girls wore white jackets and plastic goggles as they ground down gritty substances in the aforementioned mortar, the smell of rotting fruit – or nail varnish, perhaps – drifting into the corridor. Other times they spilled India ink onto thin slivers of glass, cooing as they peered at them through the lens of a microscope.

Their stories matched up when asked what they were doing –

‘We’re marking out the boundaries of cells,’ they said.

Or ‘We’re using chromatography to distinguish the pigments within leaves.’