Dual

At the beginning of the first episode at a construction site, an alien artifact is found. The foreman orders it destroyed. The workman that found it throws it away but in a parallel dimension, the workman keeps it. In one dimension, war is waged for control of the  alien technology while the other is at peace. From the peaceful world, Kazuki is  able to see in "visions" some of the battles that rage and devotes a web site to it. Through this web site he meets Mitsuki, whose father is a scientist who suspects this dimension exists and has a machine that can prove it. One thing leads to another and Kazuki finds himself in a parallel dimension where the enemy calls ahead to arrange battles.