The Pokemon Company officially unveiled The Thieves and the 1,000 Pokemon for Japan, a 3DS eShop game that intertwines the series' critter-capturing with the system's StreetPass functionality. Players find and collect sticker-like versions of Pokemon using StreetPass, and then use their army of pocket monsters to take down thieves and retrieve their stolen loot.
The game will be available for free in Japan between June 5 and September 30 - there's no word on whether or not it includes any in-app purchases. As for a Western release, while Pokemon games tend to make their way overseas, this one may take a while.
The Thieves and the 1,000 Pokemon features characters and promotions tied to the new film, Pokemon the Movie: Diancie and the Cocoon of Destruction. The film hits Japan on July 19, and while it's likely to receive a Western release, going by previous films it'll take a few months at least. So if the game is going to get a Western release, it seems likely it won't be at the same time as Japan.