The setting is a futuristic Japan in which the country is divided into the City and the lawless D.Zone. The citizens who live in the safe city have IDs and are implanted with chips that allow them access to everything (hence they're known as Chips). People who live in the slum-like D.Zone are either Lost (from the city but lost or sold their chip), Visitors (foreigners with no chips) or just plain unlucky enough to be born there (Next).

Teenagers Tsugumi and Dail are childhood friends. Both are orphans living in a city called Eden and have only each other to support.

Tsugumi works at a recycling plant. On his way home from work one night, Tsugumi found a sad-looking Dail in the park. He wanted to be left alone. "Tsugumi...I'm sorry.." were the last words he heard from Dail.

The next morning, the police are at their house and Dail is nowhere to be found. It turns out that Dail has been accused of killing his uncle and is currently missing. He can't be found anywhere in the city and was last seen near the boundaries of Eden and D.Zone.

Frantic to find Dail, Tsugumi leaves the safety of Eden behind and ventures into the dangerous D.Zone...

[Edited from Aarin Fantasy Forums]