A World Apart (The Liberty Trilogy #3)
Gretta Curran Browne

Now a close friend of Robert Emmet, Michael does everything in his power to help the young aristocrat succeed in his revolutionary aims, but traitors abound everywhere, attempting to bring down both young men.
A winner, a fighter, a survivor, Michael remains free and undefeated, but his friends all know that the greatest danger to his freedom and his life, is the girl whom Michael is so passionately in love with, Mary Doyle. All are certain that if Michael falls, it will be because of her.