"Nepobedivo srce" is a Serbian television series that follows the story of a young woman named Dara who is determined to avenge the death of her father. Set during World War I, Dara joins a group of guerrilla fighters in order to fight against the occupying forces. Along the way, she faces numerous challenges and obstacles, but her unbreakable spirit and determination keep her going. As she navigates the dangerous world of war, Dara also finds love and friendship, making her journey even more complicated. The series explores themes of love, loss, friendship, and resilience in the face of adversity.