At his request, she turned her "traitor" father over to the Nazi party. For this action, she was awarded the Iron Cross Second Class as a "Hero of the Fatherland" and gained closer access to Deputy Führer Melakon.
She helped Captain Kirk and Spock stop Melakon from launching his genocidal "Final Decision" invasion against the planet Zeon, and end the Nazi regime. To do so, she urged Kirk to order the Enterprise to intercept the Ekosian invasion fleet and destroy it. However, Kirk objected to that distastefully violent option and managed to get Führer John Gill to cancel the attack instead. (TOS: "Patterns of Force")