The Book of Autumn by Molly O'Sullivan

For readers of Adrienne Young, Olivie Blake, Hazel Beck, and Leigh Bardugo’s Ninth House, a spellbinding debut about ambition, privilege, second chance romance, and ancient magic set at an enchanted school tucked among the red mesas of the New Mexico desert, where a formidable pair of magicians are summoned to pursue an alleged killer.

Try as she might, anthropologist Marcella Gibbons can't escape the fact that she's a dimidium, one half of a formidable pair of Magicians, forever tied together to enable the other's powers. After a tumultuous final year at Seinford and Brown College of Agriculture (and Magic) in rural New Mexico, Cella felt more than a little uneasy about returning to the sun-drenched desert campus ever again. She'd cut ties with her other half—the charming and rugged rancher Max Middlemore—and sworn off Magic, academia, and heartache for good.

Until Max turns up at her door, grinning under his cowboy hat for one last favor. Something is shifting at her alma mater, something bigger than anyone understands. One student is dead. Another is floating midair in the infirmary, growling guttural nonsense and terrifying the staff. Their best, perhaps only, chance to intervene requires Cella and Max to work together. But the origins of the disturbances lie centuries ago. To unravel them, Cella will have to confront the truth about her past—and Max. Because she might be challenging a power she could never rival alone . . .