Charles, With Love

Charles Lockwood's assignment was supposed to be easy-to escort the princess to the neighboring kingdom, poke around a bit, and get out and return to his employer before anyone noticed him. But his plans fall apart when they are attacked on the road, their party slaughtered before his eyes. He makes a stupid, impulsive decision to save the princess.
Only to discover she's no princess at all. She's a stand-in.
Emmaline Blythe has been threatened at knife-point to follow through with a marriage in the princess's stead. But when she's rescued from mercenaries by a handsome stranger with a helmet stuck to his head, she is forced to lean on him for protection from her numerous enemies who want her dead.
But Charles is keeping secrets. Lots of them. Can she trust him to keep her safe? Is keeping his dangerous company worth the price of her freedom? Or will the darkness of his past catch up to them, threatening their lives and their blossoming feelings for one another?