Love After Waterloo by Suzi Love.
When Lady Melton and her son, Daniel, are forced to join antagonistic Captain Belling and the last group of wounded British soldiers evacuating Waterloo and traveling back to London, she expects clashes with army deserters, both French and British. What she doesn’t anticipate is how much she and her son will need the belligerent Captain after they reach London. Can they build a life together despite his wounds and her dead husband’s family? 

“I remember who you are, Lady Melton,” Captain Belling said in a cold voice, barely glancing over his shoulder at them. “The only thing I don’t know is why the hell you and that child are still anywhere near Waterloo, when all women were ordered to evacuate a week ago.”

“That child has a name, Captain. His name is Daniel, or if you are a  stickler for formality, Viscount Melton.”The captain turned and frowned down at her son, who stared back at him with blatant curiosity and a small amount of animosity, as forthright as any young and intelligent child. Even at his young age, Daniel was a shrewd judge of character, and had been instructed by his uncles to be careful about trusting strangers. When the Captain turned back to the tattered maps spread over his makeshift desk, Anne ignored his unspoken dismissal and used the time to observe the infuriating man without having his condemning gaze fixed on her, as it had been a week earlier at the Duke and Duchess of Richmond’s extravagant Brussels ball. If she and Daniel were to travel with his group of wounded soldiers, Anne wanted to learn as much as possible about their leader. Her son’s survival depended on her being well informed and prepared for any eventuality.

Dust filtered down through a gaping hole in the high roof and settled in the Captain’s hair, turning it a darker brown than his normal golden yellow, though a bucketful of dust wouldn’t make any difference to the state of his stained uniform. His left pants’ leg had been sliced open to the knee, the two sides pinned clear of the large bandage winding down most of his leg, while a spindly wooden crutch was propped against the table.

His large physique had attracted her even before their dance at the ball, though his striking physical attributes didn’t compensate for his belligerent attitude, or for his obvious displeasure at encountering her both in Brussels and near the battlefield. Still, the Captain had undoubtedly scowled in a similar fashion at many women he’d met either in Brussels or at Waterloo, as she’d heard him spout his narrow-minded view at the ball to his fellow officers. The Captain believed that in the vicinity of battles only men should be allowed. Not women, and especially not ladies.

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