Unexpected Pleasure by Candace Camp

Had Theo Moreland, Marquess of Raine, killed her brother? Journalist Megan Mulcahey had to know. A woman working in a man's world, Irish–American Megan is used to fighting for what she wants, but Theo may prove her greatest challenge yet.

Heir to a dukedom and powerful beyond Megan's wildest dreams, Lord Raine is also sinfully handsome and supremely intelligent. Regardless, Megan is determined to discover if Theo is responsible for her brother's suspicious death–and to find out what became of the treasure the men were seeking in the South American jungle. But first she must cross the Atlantic and infiltrate his household any way she can

The dashing explorer had always been a restless adventurer, plagued with wanderlust. But then feisty Megan came to Broughton House as governess to his younger twin siblings Suddenly, there is no place Theo would rather be than home, unable to deny the strange pull of attraction between them, or the swift and immediate desire that troubles and excites him.

Theo's seen beauty like Megan's only once before–in a fever dream. But why is this delicious vision snooping around his mansion like a common thief?

As the threads of the mystery grow ever more tangled, Megan and Theo must make a vital choice: continue to cling to the ghosts of their past or trust each other to be their future.