Enlightenment by Sarah Perry

Thomas Hart and Grace Macaulay have lived all their lives in the small Essex town of Aldleigh. Though separated in age by three decades, the pair are kindred spirits - torn between their commitment to religion and their desire for more. But their friendship is threatened by the arrival of romantic love. Thomas falls for James Bower, who runs the local museum. Together they develop an obsession with the vanished 19th-century astronomer said to haunt a nearby manor, and whose identity might finally be revealed when a startling discovery is made. As Thomas fears a broken heart, he comes to find solace in astronomy: might it offer as much as earthly or even divine love? Meanwhile Grace meets Nathan, a fellow sixth former. They are drawn recklessly together, but quickly pulled apart, casting Grace into the wider world and far away from Thomas.