The Duke’s Suspicion by Susanna Craig

An English war hero must unlock the secrets of an Irish beauty’s heart . . .
Named for the heather in her native Ireland, botanist Erica Burke dreams of travel—somewhere she won’t be scorned for her scientific interests. Instead, a storm strands her with cool and commanding Major Tristan Laurens, the Duke of Raynham.

An unexpected heir, Tristan is torn between his duties as an intelligence officer and his responsibilities as a duke. A brief return to England to set his affairs in order is extended by bad weather and worse news—someone is after the military secrets he keeps. Could the culprit be his unconventional Irish guest? He needs to see her journal to be sure, and he’ll do what he must to get his hands on it . . . even indulge in a dangerous intimacy with a woman he has no business wanting.
Erica guards her journal as fiercely as she guards her heart, fearing to reveal a side of herself a man like Tristan could never understand. But though she makes Tristan’s task infernally difficult, falling in love may be all too easy . .