The game is set in The City. It always rains, and there are no adults; they are all gone. The remaining kids struggle to survive, there are gangs and the Sirens of the Storm that lurk in the water.
In Root, unlike the board game, you're not controlling armies. You're playing as an outcast from normal society, and you're living in the space between those communities.
Demigods is a great looking RPG project from Jason Mills. It uses the Powered by the Apocalypse game engine and lets you play a demigod from any belief system you fancy and in a modern setting.