What is Xi? It's hard to tell from the "trailer" that was released only a few days ago. Now that it's live, it's much easier to decipher what's going on. This is PlayStation Home's first ARG (Alternate Reality Game), created by nDreams.

Xi is now live in both Europe and North America. Simply seek out the graffiti on the right in the Home Plaza and you'll be transported to the game Hub. It's at this point that you realize this isn't just another Home space, as the first thing you'll encounter when you enter the Xi Hub is an honest-to-goodness cutscene.

The cutscene introduces you to Xi itself, the Hub and one of the game's characters, Thom. You're immediately tasked with finding three pieces of paper littered around the Hub in order to continue with the story. There are a couple of missions to complete within the Hub right now, but from the looks of things there are plenty more to come.

There's a large screen at the end of the room which shows a "weekly recap," along with a robot called Stapler who will give you optional missions to carry out once you're fully registered. A newsfeed on one wall shows any Hub updates, as does a ticker feed above the teleporters. Speaking of which, they've yet to be activated but will no doubt lead to other game areas in the future, as will a pair of large metal doors.

It looks like the main story hasn't started properly yet. We're hoping for some collaborative tasks that will require teamwork but, even if not, Xi has already altered our perceptions of Home, showing us things we didn't think were possible in the service. Like a lot of ARGs, Xi makes use of the internet by posting clues and puzzles on external websites. You can access these from within Home by using one of the Hub's many Online Gateway screens.

So, if you've been looking for something to actually do within Home, this might keep you busy for an hour or so today. It's intrigued us enough to go back and see what changes after a week or so, but mostly it has us asking why other Home spaces aren't nearly as cool. We had no idea cutscenes, the HoloPAD interface, item collecting and story-driven voice overs were even possible within Home. More, please.

This article was originally published on Joystiq.