Sharpe's Fury: The Battle of Barrosa, March 1811 (The Sharpe Series, Book 11) by Bernard Cornwell
Captain Sharpe has to protect a philandering diplomat and, deserted by his ally, faces the enemy.
In the winter of 1811, the war seems lost. Spain has fallen to the French, except for Cadiz, now the Spanish capital and itself under siege. Inside the city walls an intricate diplomatic dance is taking place and Richard Sharpe faces more than one enemy.
The small British force is trapped by a French army, and their only hope lies with the outnumbered redcoats outside refusing to admit defeat. There, in the sweltering horror of Barrosa, Sharpe will meet his old enemy Colonel Vandal once again.
Soldier, hero, rogue - Sharpe is the man you always want on your side. Born in poverty, he joined the army to escape jail and climbed the ranks by sheer brutal courage. He knows no other family than the regiment of the 95th Rifles whose green jacket he proudly wears.