Sensible Poppy Featherstone has always known that her duty would be to marry well, for her younger sister Anise is capricious and romantic. Yet Poppy longs for a happy ever after, a true union of like minds. She thought she'd found just that in Dougal Mackay, the Earl of Reay, a relative of her sister-in-law. Yet after he scandalously kisses her in a private garden, he flees, leaving her alone with no explanation for a year. Then, the sudden death of their father forces Poppy and Anise to rely on the charity of family members, moving them to the townhouse of their half-brother. Grief-stricken, Poppy prepares to endure the change as she has everything else in life: with grace and logic.

When Dougal finds out that Poppy is staying at his sister's house, he rushes there. He's never been able to forget her, and he vows to help Poppy and her family through this difficult time. Except when Dougal was nineteen, he entered into a fool's bargain: if he were not married by twenty-nine, he would wed the young lass he'd just met in the drinking hall. Dougal never thought the woman would take him seriously—until he gets a letter that she's coming to Edinburgh and expects him to honor the terms of their drunken agreement. Dougal's heart belongs to Poppy, but his honor may force him to wed another.

Just as Poppy discovers Dougal's apparent engagement, her family is forced to relocate again, this time to a small country village. Dougal is determined not to let her go. They might still have a chance if he can convince Poppy to wed him before his twenty-ninth birthday. Ultimately, it is not sense that may save their romance, but sensibility.