Among the many surprises pre-loaded into the 3DS, Nintendo's next big handheld device, the biggest is that the thing is packed with a hidden role-playing game. It's no Final Fantasy or Dragon Age. It's something simpler and, arguably, more important.

It appears to be a gateway game, something that might transform a Brain Age gamer into a Dragon Quest gamer, or, to stereotype a little, something that might turn a grandma into the kind of gamer her grandson is.

The little game that could do this is called Find Mii.

It is hidden, improbably, in the 3DS' Street Pass Mii Plaza. The Plaza is a pre-loaded application that displays the Mii avatars that a 3DS owner collects simply by having their 3DS come within close wireless range of other 3DS systems. The machines communicate if both users have allowed Street Passing and can transfer data even if both systems are in sleep mode.

Find Mii is one of two "play" activities for your Miis to participate in. The less interesting one involves piecing together a jigsaw puzzle. Each collected Mii grants you a new piece for the puzzle — or so it seems, impossible as it is to test such a feature in New York City where very few other people have a pre-release 3DS from Nintendo. If 3DS owners can handle a puzzle game, they should be able to step up into Find Mii. In the game, the 3DS owner's Mii is imprisoned, but can be freed by the other Miis who show up in the system. The player controls these new heroes in a series of battles. If you haven't encountered new Miis, you can cash in Play Coins — virtual currency earned by walking around with the 3DS — and pay for some wimpy mercenary heroes.

The more friends you make, the more 3DS systems you connect to, the bigger the band of heroes you'll have to rescue your Mii. That system resembles the friend-request roots of FarmVille and other Facebook games. While those games connect the advantages of proselytizing a game with the need to pay real money in small increments in order to progress, Find Mii will proceed more or less for free, once people have plunked down $250 to own one of these new 3DS systems. In either case, the more you connect, the better you do. You play in drips and drabs, hoping to make progress over a long period of time.

Top Nintendo people have been talking for several years about gateway games, pleasing and relatively unthreatening experiences like Mario Kart or New Super Mario Bros. Wii that could the millions of people attracted to video games via Wii Fit or Wii Sports into the kind of people who get excited when a new Zelda or Metroid is coming out. They've now put a gateway game into their next system. Let's see how many people they convert.

And let's see how fun this kind of social gaming is on a Nintendo platform.