In 1809, Sir Arthur Wellesley, commander of the British forces in the Iberian Peninsula, prepares to invade French-controlled Spain.
He orders Lieutenant Richard Sharpe and his band of "chosen men" to accompany the arrogant, incompetent, newly arrived Sir Henry Simmerson and his South Essex Regiment on a mission to destroy a bridge vital to French troop movements.
His fears are realised when a hidden French cavalry unit overruns the British; Lennox is fatally wounded and the King's colours are lost.
Afterwards, the dying Lennox asks Sharpe for a French Imperial Eagle to wash away the shame of losing the colours.
At just the right moment, Sharpe and his riflemen attack the wavering French soldiers in the flank, sending them into headlong retreat.
While both the novel and the film follow a similar plot, many of the characters and events are altered from the former, often in order to minimise production costs.