The once famous and well respected scientist Zorndyke has bred a new genre of living being, one that thrives on the oceans and lives to destroy humans. Zorndyke believes it is time that the humans were relieved of their rule of the earth. It is up to Blue Submarine No. 6 and the rest of the Blue fleet to put an end to Zorndyke's madness and creations. (Source: ANN)

Set in 2142, Wonderful Days depicts a world that has been nearly destroyed by environmental pollution. Human life as we know it is almost extinct, and only a few were able to pull through the collapse of Earth's ecosystem. In order to deal with the chaos, a city named Ecoban was created. The city uses the very pollution that caused the disaster as an energy source.

However, although the initial plan was successful to an extent, it didn't just create a new source of energy, but also an elite group of people. This prestigious faction believes that they are above the system, and are not willing to accept survivors from outside the city unless they are put to work as laborers.

Among the people 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 that he feels for his childhood friend Jay. Unfortunately, Jay may be more interested in her security commander Cade than in Shua, and thus a love triangle is formed. Not only does Shua have to deal with the heartbreak, but he must also find a new way to survive in the crumbles left from the once-beautiful planet Earth.

Eighteen-year-old Dale Reki is a skilled, kind, and respected traveller, acknowledged as one of the leading adventurers in the city of Kreuz. One day while on the hunt for magical beasts, he comes across a sweet devil girl named Latina. She is alone, dressed in rags, and bears the devils' symbol of a criminal: a broken horn. Concerned for her wellbeing, Dale decides to ensure Latina's safety by bringing her to his home, eventually leading to him adopting her. Latina is sweet, innocent and compassionate, charming Dale beyond his expectations. He begins to enjoy the life of parenthood— experiencing the trials that come with raising a child and coping with the heartache he feels whenever his busy lifestyle as an adventurer parts him from her. Although work and life as a new parent become reassuring constants for Dale, the mysteries surrounding the girl remain. Why was Latina alone in the forest, and why does she harbor the symbol of a criminal? At the same time, Latina also begins to learn about the world and herself as she adjusts to her new life with Dale. [Written by MAL Rewrite]

During the 21st century, humanity attempted to colonize Mars by sending two species which could endure the harsh environment of the planet to terraform it—algae and cockroaches. However, they did not anticipate the species' remarkable ability to adapt. Now in the 26th century, a lethal disease known as the Alien Engine Virus has arrived on Earth, and the cure is suspected to be found only on Mars. The problem is, Mars in the present is overrun by creatures known as "Terraformars," incredibly powerful and intelligent humanoid cockroaches that mutated from those originally sent to the planet. The Annex I team, consisting of a hundred men and women genetically enhanced with characteristics of powerful organisms from earth, has been sent to Mars on a mission to find the cause of the Alien Engine Virus and to help cure humanity—signalling the start of the crew's fight for survival. [Written by MAL Rewrite]