the people who sang like birds

Ferll is having a totally normal day, normal as one could expect with a day full of work and war. The war has dragged on for a year now, with no signs of slowing as this army takes down city after city. He's overworked and worried about when his city will be taken. And then, his brother goes missing.
The only evidence he and his friends find is a feather, too big to have been a bird's.