On December 21, 2040, humanity was visited by an alien force, armed with power unmatchable.

There was no way of stopping the spaceborne assault, nothing thrown at them had any effect.

It was only by an unfathomable miracle that the aliens vanished as suddenly as they had arrived.

But Earth's salvation came at a heavy cost; the ten day onslaught claimed three billion lives.

In the aftermath of desolation, humanity has been working tirelessly, anticipating a second invasion.

At the forefront of Earth's defenses stand the HERO, humanoid mecha developed using alien technology.

Schools scattered across the globe have been established to train the pilots that are humanity's best hope.

Now, in 2048, the black door shall be opened unto a new day...