On the Eve revolves around a girl called Elena, who meets a Bulgarian boy Insarov and soon falls in love with him. Secretly marrying in the Bulgarian revolutionary, Elena invites the ire of her parents, who had hoped to marry her to a more respectable suitor. On the outbreak of the war, Insarov's call home only complicates matters further. Insarov returns with Elena to Bulgaria, but dies on the way in Venice. Elena is never heard of again.

这部小说围绕俄罗斯姑娘埃琳娜展开。埃琳娜遇上了保加利亚人因萨罗夫，不顾父母反对嫁给了他。但在埃琳娜跟随因萨罗夫返回保加利亚的途中，因萨罗夫因病逝世。坚强的埃琳娜仍然只身前往保加利亚，成为一名战地护理人员，继承丈夫奋斗一生的事业。