The Faithful River, by Stefan Żeromski
A badly wounded soldier, near death, stumbles into a mostly-deserted manor house. The only people there are Salomea, a young woman whose father is off fighting, and an elderly cook. They take the soldier in and hide him during his long, slow recovery.
Josef Odrowaz is a dashing young nobleman -- or he was, before the Russian troops slaughtered every wounded man on the battlefield. Now he is only barely alive, and the locals dare not help him. Salomea takes him in, but troops arrive at her house every couple of days, demanding food she doesn't have and searching for hidden rebels. As Josef recovers, he and Salomea fall in love.
The river runs near Salomea's home and though it does not appear all that often, it proves itself to be more faithful to the Polish cause and to those to run to it for shelter than flawed human beings are.
It sounds like a simple plot, but in fact the novel is quite complex. Stefan Żeromski examines the contradictions of the uprising and the war -- the Polish struggle for independence that is idealistic in concept, but brutal to the actual Poles. Salomea is faithful to the Polish fight for freedom at the same time that she rails against its leaders for being so idiotic as to start a doomed uprising against a massive power like Russia.
The introduction to the novel says that Stefan Żeromski is venerated in Poland as one of its great novelists, but isn't well-known in English. He's certainly worth searching out and reading.