In far 2107 ED (Era Digital) ranks are computed for every human. They are incorporated in human DNA and used everywhere: marriage, bank account, carrier .. In this world nothing can be said to be certain, except ranks and DNA debts.
In the far future when everything is digitalized an young man is accused of using paper memories. He is punished and his rank is eliminated from the system. Living without rank is like living without oxygen. No one can survive.