On the super continent Gyro, humanity is separated into eight clans. These clans are the seven sins and the sinless. The seven sins control all the land. The sinless care for the young and the elderly, but many of the adults can not be sinless and must choose to a sin to join. 
Jacob is one such person. He's starting to come of age and is unable to stay in the sinless' sanctuary. He chooses to spend his days in the large desert territory of the Envy clan.