The Antarctic thaws and it is an era when most of the land has been submerged in water. The extinction of Mankind already draws near. Mankind who were born from Adam and Eve, were now deteriorating as they repeatedly get cloned from generation to generation. Things essential for the survival of living things were lost. 
Even so, the ones remaining cling on to survive... 
"We should get what we need for survival from something else...!" 
And so, a mere small group of humans began a new life upon the surface of water, exhausting the resources of each and every other living thing to survive. In the end, they discover people who posess a huge quantity of things necessary for survival. 
The young men who posessed such things continues their journey even today, to escape from those who were pursuing them. They just wanted to find that something somewhere. They were seeking for the one and only "help" there was... 
(Source: AnimeNfo)

Kei