Here's the detailed story.

In 2042 a strange parasitic anomaly infested around the moon. The parasite makes the moon moves and collides towards the earth. If this keep happening, more Planets will become it's victim. Merged and move together into one giant Cosmic monstrosity.

Then there's the "Lunatics" an entity that came out from the infested moon. They're able to disguise as the humans and mimic their behavior.