First portion consists of harmless prologue chapters irrelevant to the plot, but the plot goes like this: Loki (the Norse God) slowly recruits people by passing off as a harmless bystander into Inglip's (yes, the internet meme) following.
Continue: Real plan, however, is to lure those people AND the current Gropagas into a ritual that summons ZALGO. It's supposed to be a trilogy, so ZALGO won't appear as the final boss until the final game.