War Is Over!

In an alternate WWI reality, a heroic pigeon delivers messages across the battlefield, from one side to the other. The messages are exchanged by two soldiers on opposite sides, who, unaware of who their opponent is, are playing a game of chess against each other. As the fighting and the game both escalate, they continue to exchange their chess moves, delivered by the brave pigeon. Whoever wins the game, what's certain is that there are no winners in war.