She was deprived of her inheritance and they wanted to force her into marriage. But she chose freedom and ran away. Now young Johanna von Allersheim is forced to impersonate a man. She and her twin brother Karl find refuge with Adam Osmanski, the commandant of an impregnable Polish fortress. But the distant relative is not happy about unexpected guests. Moreover, he knows that in front of him is not a man, but a girl. Johanna continues to play her role, risking her life. Suddenly, the troops of the Ottoman Empire begin an attack on Vienna and all the men in the fortress are ordered to join the ranks of the royal army. What if it's too late to reveal the truth about yourself? And what will be the consequences? But Johanna has no other choice: now or never...