The opening scene of Arms and the Man by George Bernard Shaw introduces the context, the main characters, and the central conflict of the play.

In this, as in all of Shaw's plays, it is important to read the stage directions carefully as Shaw uses them to impart significant thematic and other information. The first thing we learn from the stage directions is that the play is set in Bulgaria during the final stages of the Serbo-Bulgarian War of 1885. The decor is described as "half rich Bulgarian, half cheap Viennese," a description that shows the class and cultural tensions of the play, with the Petkoff family counting as wealthy and important locally, but as unsophisticated provincials from the point of view of Western Europeans.

Raina's discussion with her mother shows her fundamental ambivalence towards the romantic worldview. On the one hand, she has an almost schoolgirlish infatuation with Sergius and a naive view of the glories of war, but her basic common sense shines through in the lines:

. . . perhaps we only had our heroic ideas because we are so fond of reading Byron and Pushkin, and because we were so delighted with the opera that season at Bucharest. Real life is so seldom like that . . .

With the entrance of Bluntschli, we get the key conflict in the play. Just as the romantic vision of Sergius competes with the sensible presence of the "chocolate cream soldier" for Raina's hand in marriage, so too does romantic idealism compete with sensible pragmatism for her intellect. 

Critically, one can also look at the way Shaw is commenting not just on how realistic and romantic viewpoints compete, but also on literary genres. He tends in this scene to compare silly or romantic behavior to works of art, comparing Sergius to "an operatic tenor" and Don Quixote and contrast that with the ordinary everyday reality of the Swiss mercenary.