A bunch of people led by a guy with possible paranoia issues wind up making a time travel device.
Slow to start and confusing as fudge, but it picks up and you start putting two and two together to make sense.
Also, I loved the lampshade right after the intro in episode 1, where they briefly discuss whether someone would know if they were in a videogame; a homage to the fact that this was a Visual Novel before this.