The Duke’s Treasure by Ellie St. Clair

A duke intent on finding a treasure. A Spanish woman with nothing to lose. A legacy in the making.

Edward, Duke of Sheffield, is expected to find a bride and take on the duties of his noble title. He would much rather, however, chase adventure and hunt treasure. He makes a promise – he will reluctantly embrace his future, after one last journey. One that takes him to the shores of Spain.
As the young widow of a Spanish marquis, Mariana vows to never give her hand – or her heart – away again. Especially to an English duke with unbelievable tales.
Edward’s mission to uncover a legendary treasure faces one obstacle – a Spanish woman with nothing to lose. When he begins to feel something for her, can he convince her to trust him enough to reveal her secrets – and her heart?
This is the prequel to the Reckless Rogues and can be read before or after the five main books of the series.