The meeting of Raina and Captain Bluntschli drives the central plot and thematic concerns of the play. Before the meeting, we have a dialogue between Raina and her mother which serves as exposition, letting us know that Raina is engaged to Sergius, who is a soldier in the Bulgarian army during the Serbo-Bulgarian War of 1885. The play takes place shortly after the Bulgarian victory in the Battle of Slivnitsa.
Captain Bluntschli is a Swiss mercenary fighting for the Serbs who has narrowly escaped being captured by the victors. He climbs up Raina's balcony to hide. His very appearance undermines Raina's romantic notion of a soldier. Although he has a gun and threatens her, he is far from heroic. Not only is he afraid of death and capture, it becomes obvious that he is almost more scared of Raina than she is of him.
Before the meeting with Captain Bluntschli, Raina expressed conventionally romantic notions about both love and war, in which men were cast as Byronic heroes, but she also mentioned that she had doubts about the reality of this romantic ideal. When she meets Captain Bluntschli, not only do her views change, but so does her role. At the same time that he undermines her ideas about the romantic nature of war, he also emphasizes his dependence on her.
In her engagement with Sergius, Raina was the conventional girl who stayed at home while men saved the country through their heroism. In her interactions with Captain Bluntschli, Raina becomes a strong woman whose quick wits actually save Captain Bluntschli from capture, as well as providing him with food, warm clothing, and a safe place to rest. The beginnings of the romance represent the evolution of Raina from a romantic girl mainly concerned with her social position to a strong woman using her intellect to good purpose.