The second book in the series finds Sharpe and his men reunited with the British army, which is about to resume the offensive under the command of Sir Authur Wellesley, the future Duke of Wellington, to retake Spain from the French.
Sharpe is under the command of an incompetent boob of an amateur colonel.
Sharpe has to fight the French and defend his career and his men's lives against his own superior. And his Spanish allies are fatally inexperienced. There was a simple mathematics to what happened next. The Spanish had shot their volley and would take at least twenty seconds to reload. A galloping horse could cover two hundred yards in much less time.