Harrod-Eagles, Cynthia. Ashmore Castle series

England, 1903. Giles, the Earl of Stainton, has fled from his stifling duties to resume his research in Egypt, leaving behind his wife Kitty, and his infant son. Kitty, still reeling from Giles' sudden departure, struggles to keep spirits high in the castle and establish herself as the true mistress of the house, an impossible task given how many secrets the inhabitants are hiding from her... The Earl's younger sisters, Rachel and Alice, are both pursuing forbidden romances, and his brother Richard begins a new business venture, spurred on by his clandestine lover. And below stairs, a shocking crime sends distrust rippling through the staff, more so when one of their own is accused. Kitty must draw on her strength to keep the castle from crumbling around her, but with her marriage to Giles left uncertain, and a surprise of her own to conceal, can she ever take her rightful place as true head of her household?