The narrative follows Debby Mason, a spirited young girl whose father leaves to join the revolutionary fighting and whose separation forces her into the care of a strict neighbor; deprived of home and her treasured drum, she yearns for freedom, practices her drumming in secret, and ultimately joins the militia as a drummer called Molly. The story traces her experiences in camp and on campaign, the friendships and hardships that shape her, moments of bravery and sorrow, and the recognition she wins from comrades and commanding figures while exploring themes of loyalty, resilience, and the costs of war.