This is Not an Umbrella(2011)

In a world where 'The Peace' hangs in the balance, Benjamin has found a way to bring harmony to his people. He is the enforcer of 'The Rule,' a system based on a contract that has brought two rival populations to a co-existence. One population is forever doomed to the Sun, while the other is condemned to the Shade. The consequences for breaking 'The Rule' are fatal until Benjamin becomes curious.