Raina Petkoff, the fashionable wax-doll daughter of Major Petkoff, was betrothed to the hypocritically romantic Sergius Saranoff. But on the night of gun-battle, the Serbian Major, Bluntschli, entered secretly into Raina's bed-chamber to shock and disillusion her in matters of heroism in war and love. Bluntschli, a professional soldier, deliberately and with all the verbal weapons of wit and sarcasm, demolishes Raina's false impressions of patriotism and heroism. Bluntschli is a professional and experienced soldier, and knows that 'nine soldiers out of ten are born fools'. He has escaped his persuers and taken shelter discourteously in Raina's bed-chamber by climbing the rain-water pipe because he wants to avoid death as long as he can. By the end of the opening scene, Raina grows fond of the enemy having fallen asleep in her bed.
Although Sergius has won the battle of Slivnitza against the Serbian artillery with an incredible cavalry-charge, to be worshipped by Raina as her 'soul's hero', he is not promoted in the Bulgarian army. When Sergius returns, frustrated and cynical, he seduces and flirts with the Petkoff house-maid, Louka, and the same is detected by Raina. By the time Bluntschli re-appears to return Major Petkoff's coat, Raina is in love with her 'chocolate-cream soldier'. She and her father are also full of admiration for the Swiss professional for his expert handling of military issues far ahead of Sergius. Bluntschli also scandalises Sergius as well as Mrs.Petkoff by his matter-of-factness as a soldier and as the son of a fabulously rich hotelier, seeking Raina for his bride.