Story
Plot- Spoiler Free
In the year 2009, Yuji Kaido is an average young adult male diagnosed with a serious disease and is put into cryogenic stasis until a cure is found. Twenty-two years later, he is awakened in the midst of a raging battle between armored soldiers and insectoid beings called the "Blue" which have overrun the Earth.
The group of soldiers are from an orbiting space colony collectively called Second Earth and were ordered to recover "sleepers" around the Earth. Among them is the soldier Marlene Angel. On the journey to Second Earth, Yuji meets many of the humans that were left behind during the evacuation due to limited resources.
Yuji falls into a deep depression as he recognizes the destruction around him and his own inability to save those he cares about. During their travel to Baikonur space base through the mountains, Yuji and Marlene start to develop a bond that starts to soften her sharp edges. This is a turning point for Marlene and her feelings for Yuji are quite clear for the rest of the series.
Upon arrival, Marlene and Yuji are separated, and Marlene is sent back into training at the education station. Not knowing what happened Yuji, Marlene rebels and is bent on finding him. When she does, she finds he is being trained to use a new specialized "sleeper"-specific Armor Shrike (A.S) called the "Double Edge", a battlesuit that is much stronger than the originals used in war against the Blue.
After intensive training, Yuji and Marlene return to Earth with two other "Sleepers" named Tony Frost and Alicia Whistle. They and the other forces of Second Earth battle the Blue. They become successful at destroying a few of the largest nests before they head back to Second Earth. However, the battles begin to have a negative effect on Yuji who gives very little regard for human life and is completely obsessed with being better than Tony at killing Blue. Yuji's actions deeply concerns Marlene and she begins to know something is wrong.
Shortly after returning to Second Earth, the High Council orders the "Sleepers" on a second offensive against the Blue. Marlene is separated from Yuji once again, but in his current state he does not seem to care. Seno, the head of Second Earth's science division, leads the "Ark" rebellion taking control of the military, lunar resource, and education stations of Second Earth. The High Council escapes to and retains control of the medical station. During this time Marlene learns about the nature of the illness that put Yuji in stasis, the source of his abilities, and the source of the Blue Insectoids.