Enraptured By the Highlander by Lydia Kendall

A dark prison shelters their love but the truth tears the canvas of their passion…
Adelaine Watson, daughter of the Earl of Daffield, anxiously awaits her brother’s return from war. But when her father returns, he brings back someone else: her brother’s murderer.
Falsely accused of murdering an Earl’s son, Caelan McLagen, Laird of Loch Mahrais, has accepted his death sentence. That is until the alluring Adelaine starts visiting his cell and he feels the warmth of hope.
Convinced of Caelan’s innocence, Adelaine falls madly in love with him and is desperate to find a way to stop her worst nightmare from becoming reality.
When the only eyewitness to her brother’s death dies, Adelaine realizes that the real murderer is closer than they thought. With Caelan’s execution hanging above their heads like the executioner’s ax, Adelaine must make a terrible choice…