Set in 2142, Wonderful Days portrays a world nearly destroyed by environmental pollution. Human life as we know it is almost extinct, with only a few having survived the collapse of Earth's ecosystem. To manage the chaos, a city called Ecoban was established. This city utilizes the very pollution that caused the disaster as an energy source. However, while the initial plan was successful to some degree, it did not merely create a new energy source but also an elite group of people. This prestigious faction believes they are above the system and refuses to accept survivors from outside the city unless they are put to work as laborers. Among those living in the wasteland outside Ecoban is a young man named Shua. He leads a very difficult life but tries to make the most of it through the love he feels for his childhood friend, Jay. Unfortunately, Jay may be more interested in her security commander, Cade, than in Shua, thus forming a love triangle. Not only must Shua deal with heartbreak, but he must also find a new way to survive in the ruins left from the once-beautiful planet Earth.